Where and when? Examiningspatiotemporal aspects of sexual assaultevents

Samantha Balemba & Eric Beauregard*Simon Fraser University, Burnaby, British Columbia, Canada

Abstract This research investigates the where and when of sexual assaults to determine what

types of sexual crimes are committed at different time and place classifications. Exhaustive CHAID

(chi-squared automatic interaction detection) analyses are conducted, examining factors associated

with crimes that were committed indoors or outdoors, in private or public places, during the day or at

night, and during the week or on the weekend. These methods are applied to a sample of 361 sexual

crime events committed by 72 serial sex offenders. The results are strikingly different dependent on

which spatial or temporal aspect of the crime is examined, which implies the complexity of sexual crime

events and their situational components. This research brings to light possible policy implications with

respect to situational crime prevention.

Keywords CHAID; serial sex offending; situational crime prevention; spatial; temporal; time and

place

Introduction

Most studies examining the offending patterns of sex offenders have neglected to consider

their spatiotemporal characteristics. However, recent policies and legislations specific to sex

offenders have highlighted the importance of investigating times and places of sexual assaults.

For instance, where and when the crime is committed is central to measures of residence

restriction, registration, curfews and community notification.

To begin to comprehend spatial and temporal patterns of sex offending requires in-depth

examination into the decision-making processes of these offenders. Why does the offender

decide to commit his crime at that time and in that location? Does he need to act in the dark in

order to not to be recognised by his victim? Does he need to act in a public location, such as a

park, to gain access to potential victims? Does he act during the day and in a private location,

such as his home, to be able to get his victim to participate in the sexual abuse without risking

being interrupted? These are not questions easily answered, especially if the goal is to

extrapolate to meaningful groups of offenders and affect policy change.

*Corresponding author: E-mail: ebeaureg@sfu.ca

Journal of Sexual Aggression, 2013

Vol. 19, No. 2, 171�190, http://dx.doi.org/10.1080/13552600.2012.703702

# 2013 National Organisation for the Treatment of Abusers

Offending process

Decisions take place at every juncture of a criminal event. Within any crime, there exist

certain procedural requirements in order for the crime to progress from one stage to another,

for which the offender creates a crime script (Cornish, 1994). These decision steps may occur

in preparation before the crime, during target selection, throughout the modus operandi (MO)

itself and in the final crime completion steps. Previous studies have elucidated pathways to

offending or offence chains specific to child molesters (Proulx, Perreault, & Ouimet, 1999;

Ward, Louden, Hudson, & Marshall, 1995) or rapists (Polaschek, Hudson, Ward, & Siegert,

2001; Proulx, St-Yves, Guay, & Ouimet, 1999) that are especially useful in addressing relapse

prevention. However, although placing great emphasis on pre-crime emotions and crime

preparation factors as well as post-crime emotions and even offender evaluations during the

assault itself, there is little to no focus on the actual crime and the decisions made therein.

More importantly, such studies examine crime as if it exists within a vacuum; that is, as

distinct from its surrounding environment. Traditional inquiries and analyses of sexually

assaultive behaviour concentrate on offender characteristics that motivate the offender*either distally or proximally*to offend. Additionally, studies often include pertinent

interactions between victim and offender before and during the assault, although still within

the vacuum encasing the criminal event. The solid theoretical and practical foundation

provided by this previous research has made it possible to move forward and begin to observe

and analyse the impact of real environmental factors outside that vacuum that have yet to be

developed within the sex offender literature: specifically, the effects and inherent constraints

of time and space. Brantingham and Brantingham (1981) refer to this important concept as

the ‘‘fourth dimension of crime’’ (p. 8)*the location in time and space in which the first three

dimensions (legal, offender and target) intersect to result in the criminal event itself. The

spatiotemporal setting of a crime has the potential to affect the commission, progression and

outcome of a crime as much as any offender- or victim-specific variable. Furthermore, the

crime commission process, in which an offender recognises a potential target and its

accompanying opportunity and takes steps to penetrate existing barriers, has been suggested

to be a result of a multistage decision process within the larger realm of environmental

learning in general (Brantingham & Brantingham, 1978). Thus, although the importance of

this fourth dimension of crime has been demonstrated clearly within criminological research

(Brantingham & Brantingham, 1981), it has barely been acknowledged within the sex

offender literature, despite its obvious implications, especially as it relates to the offending

process and crime scripts.

During any offending process or script, within any spatiotemporal setting, the decisions

made at each juncture are purported to amount to a series of rational decisions. Although not

necessarily rational in the traditional sense, decisions are always goal-orientated and adaptive,

and the best perceived option is always chosen (Clarke & Cornish, 2001; Cornish & Clarke,

1986). Research has further shown that choice of crime location is not arbitrary (Brantingham &

Brantingham, 1981; Canter & Larkin, 1993). Rather, the locational choice for crime

commission is related to the specific experiences of the offender and implies at least a crude

form of logical selection. The offender himself may be unaware of this selection process, as in the

case of an offender whose opportunities arise within his awareness space, which forms during

everyday life. Whether intentionally or not, the offender becomes aware of potential victims and

targets during non-criminal activities, and his offence locations end up corresponding to these

experiences (Brantingham & Brantingham, 1981). Thus, through day-to-day activities,

an awareness space develops, which is home to many offenders’ choice of crime location,

often due to the familiarity and comfort within this awareness space, leading the offender to

172 S. Balemba & E. Beauregard

believe that this is the safest place for him to commit his crimes. This is one of many rational

decisions that the offender must make, with his own best interests in mind (which often involve

ease of crime completion and chance of apprehension).

Derived from an economic model, this rational choice perspective assumes a cost�benefit

analysis within the mind of each offender upon encountering various decision points during a

criminal event. Thus, if at any decision point during a criminal event the balance of benefits

and costs are altered so that the offender decides the risks are too high for the expected

rewards, the crime will not take place. It therefore follows that, to prevent a crime or halt it

during its commission, the risks must be heightened while any perceivable benefits are

minimised. This forms the essential basis of situational crime prevention.

Situational crime prevention

The notion of the reasoning and rational criminal has been taken by Clarke (1980, 1983) into

the realm of crime prevention. Because the rational choice perspective informs us how

criminals think and make decisions, Clarke asserts that we can use that knowledge to prevent

the criminal behaviour that stems from these decisions. Furthermore, as Felson and Boba

(2010) succinctly sum up, criminologists can determine just how to do this without ‘‘getting

fancy’’. Researchers concerned with situational crime prevention should maintain a narrow

focus on a particular type of crime, should not try to improve human character or decrease the

internal motivation to offend, and should concentrate on preventing crime in practical,

natural, simple ways (Felson & Boba, 2010). This is the foundation of situational crime

prevention upon which policy initiatives must be based.

Situational crime prevention places a clear emphasis on the choices and decisions made

by the offender and implements physical (as opposed to social) measures that reduce

opportunities for crime (Clarke, 1980, 1983). The most effective preventative implementa-

tions are directed at specific crime types (Clarke, 1983), such as vandalism that occurs

between midnight and 3 a.m. within a deserted commercial district; simply targeting

vandalism in general is too broad an area. Although successful measures may certainly be

applied subsequently to other situations, each implementation should be tailored to the

particular time and place where it needs to be most effective.

At its most basic, situational crime prevention is concerned with the management,

original design or later manipulation of the immediate environment (Clarke, 1983). Clarke

promotes methods such as target hardening (making the objects of a crime less vulnerable,

such as implementing ‘‘Safe Walk’’ security programmes to protect potential sexual assault

victims who would otherwise be walking alone after dark) and creating defensible space

(which involves the territorial surveillance of public spaces by nearby residents, such as

providing neighbourhood watch services to protect potential victims against predation on the

streets). The clear connection to the rational choice perspective is increasingly evident;

situational crime prevention is aimed essentially at increasing the effort required and the risks

to potential offenders and, to a lesser extent, decreasing the procurable rewards. Thus, this

crime prevention method intentionally attempts to tip the cost�benefit scale by which

offenders choose whether to take advantage of a potential criminal opportunity or let it be.

Although designed originally to increase the risk and effort incurred when committing a

crime and decrease procurable rewards, more recently, situational crime prevention models

have also begun to include the removal of excuses and the reduction of provocation

(Smallbone, Marshall, & Wortley, 2008; Tilley, 2009). Excuses relate to situations in which a

crime takes place because offenders are able to justify it to themselves morally, such as if staff

within an institutional setting develop a sense of superiority and self-righteousness, creating

Where and when? 173

moral excuses to justify their abuse of children in their care*as in: ‘‘they’re all just numbers’’

or ‘‘it’s for their own good’’ (Smallbone et al., 2008, p. 170). To remove such excuses requires

implementations such as rule-setting, assisting and easing compliance and alerting a potential

offender’s conscience, such as the enactment of protocols that manage and regulate

interactions between staff and children as well as simple changes such as formalised codes

of conduct, educational posters, staff training and the prosecution of known offenders

(Smallbone et al., 2008; Tilley, 2009). Provocation involves emotions that may lead to crime

where it would not otherwise occur, such as in cases of domestic child abuse that occurs in

response to the observation of children in ‘‘provocative’’ or vulnerable settings (Smallbone

et al., 2008). To reduce such provocation situationally requires the application of systems that

reduce arousal and control triggers, identifying and removing cues that induce arousal. This

could include situations such as intimate adult�child interactions; for example, giving a child

a bath without supervision (Smallbone et al., 2008). Although the burden for such

applications would naturally fall on the family of the victim and/or offender, there would

also be many undetected offenders (or would-be offenders) searching for a way to curb their

sexual interests that would probably take advantage of these methods themselves (Chasan-

Taber & Tabachnick, 1999).

It cannot be forgotten that the factors that affect offender decision-making are evaluated

from the offender’s viewpoint (Felson & Boba, 2010). For the best results within the realm of

situational crime prevention, the most important environmental aspects to change are the

perceived costs and the perceived benefits, whether or not the actual costs and benefits have

been altered. Thus, even if a neighbourhood watch group is not overly vigilant at certain times

of day, the fact that potential offenders can easily see the signs denoting the group’s existence

and believe that it would make a child sexual abuse attempt more difficult serves the same

purpose as if there were neighbours watching at their windows every second. Alternatively, if a

concerned neighbour takes it upon himself to attempt to catch child predators and reduce

victimisation in his neighbourhood, but does not advertise his plans or join a group or

organisation for this purpose, this will have no deterrent effect (although it will probably serve

other benefits, such as the prevention of a completed sexual assault or the apprehension of

assailants). Therefore, although some situational crime prevention methods have been shown

to be more effective than others, whether due to the way methods are implemented and their

unintended consequences or whether people utilise the measures faithfully and consistently

(Felson & Boba, 2010; Tilley, 2009), the most important design feature is to make the

offender perceive greater required effort and potential risks to criminal behaviour with lower

attainable rewards.

Although it is true that situational crime prevention has most often been applied to

property crimes (the inherently more ‘‘rational’’ crimes), this does not imply that similar

tactics could not be used for other crime types as well, such as sexual offending. Smallbone,

Marshall, and Wortley (2008) have put forth a particularly promising model to apply

situational prevention principles to instances of child sexual abuse. Due to the specificity

required in applications of situational crime prevention, there are many instances where a

case-by-case analysis is necessary before measures can be put into place. However, Smallbone

and colleagues have begun to address this issue through a preliminary classification of child

sexual abuse based on the setting in which the offence takes place: public, institutional or

domestic. Using these categories, the authors suggest situational prevention measures

designed to decrease the incidence of abuse within the overall setting, rather than targeting

a specific offender or victim type. For example, offenders who target children in a public

setting may be deterred by increased formal and informal surveillance and guardianship and

their exploits may become more difficult if tools such as the internet are made more difficult

174 S. Balemba & E. Beauregard

to utilise for their offences (through the use of filtering software and police implemented

websites meant to lure offenders searching for child targets or child pornography).

Alternatively, those who offend within institutional settings would be more affected by

policies that assess and address the risks of either institutional staff or the institution itself to

remove potentially dangerous situations as well as implementing rules regarding the time

spent alone with a child. Thus, although not yet tested empirically, this situational prevention

model serves as a stepping-stone towards the use of situational crime prevention methods in

all forms of crime prevention, rather than focusing solely on property offences.

Aim of the study

It is important to investigate spatiotemporal considerations in order to identify patterns of

behaviour associated with crimes committed at particular times and in particular circum-

stances. Research must determine how, and to what extent, the offending processes of sex

offenders are influenced by spatiotemporal factors. Offenders committing their crimes

outdoors, for instance, may use completely different offending strategies compared to

offenders who choose indoor locations to offend. Once offending patterns are illuminated,

this information could be applicable to situational crime prevention efforts, especially those

that complement sex offender policy. For example, if particular crimes are more likely to

happen outdoors, these could be targeted specifically through the use of situational adaptations

to prevent those crime types that are more likely to occur, such as through targeted policing.

Additionally, it is important to learn how offenders behave in specific places and at

specific times so that situational prevention strategies can be designed and potential victims

can be educated with certain expectations in mind. It is just as important to ascertain what

will probably not happen as it is to determine what probably will happen. For example, an

offender who targets children will probably utilise a different strategy if he is attempting the

crime outdoors (asking a small child: ‘‘Would you please help me find my puppy?’’) than he

would if the offence were to occur within an institutional setting (using his position of

authority to manipulate or intimidate his victim); a cross-over between these strategies is

nonsensical and is unlikely to occur. Similarly, one rapist will be wary of using a sudden,

violent attack within a private setting where escape is difficult and another will find it difficult

to slip an undetected drug into his target’s drink while she is wandering around a public park.

This study is designed to tease some of these details apart to begin to create logical, probable

scenarios while simultaneously providing information that will aid in preventative measures.

This research delves into the where and when of sexual assault events in an attempt to

determine what types of sexual crimes are committed at different time and place categorisations.

It is important to investigate such considerations in order to identify patterns of behaviour

associated with crimes committed at particular times and in particular circumstances. The

current study investigates which MO and victim (target) variables can predict various spatial and

temporal offence characteristics in sexual assaults committed by serial sex offenders. What types

of crimes are more likely to take place at various times and in certain location classifications?

Methodology

Participants

The data consisted of a sample of 361 sexual crime events committed by 72 serial sex

offenders. Offenders were recruited if they had committed two or more sexual assaults or

sex-related crimes (e.g. sexual homicides) on a stranger victim (i.e. offenders with no personal

Where and when? 175

relationship with the victim prior to the day the offence was committed) of any age and

gender. These specifications were chosen to ensure that the sample consisted of what could be

considered the most ‘‘dangerous’’ and feared population of sexual offenders*those serial

offenders who choose stranger victims. Due particularly to the fact that, although most

criminals are not serial in nature, most crimes are committed by a serial offender (Rossmo,

2000), a specific examination of patterns that may develop within the behaviour of a group of

serial sexual offenders was especially warranted.

Of more than 1000 sex offenders who were convicted from 1995 to 2004 in Quebec, 92

offenders matched the criteria, 72 agreeing to participate (only nine of the 20 who did not

participate had refused outright; others had mental, discipline or logistical issues that

prevented their participation). Together, these 72 were responsible for a total of 361 sexual

assaults (ranging from two to 37 sexual assaults per offender).

The sample was mainly Caucasian (91.3%) with a mean age of 30.7 (standard deviation

[s.d.] �9.4) when they began their crime series. Within the sample, only 10.1% had no prior

criminal record before beginning their series; of the 89.9% who did have a criminal record,

they had an average of 2.9 charges (s.d.�6.3) for a violent sexual crime, 1.0 criminal charge

(s.d.�3.1) for a non-violent sexual crime, 2.5 charges (s.d.�4.4) for a violent non-sexual

crime and 11.9 charges (s.d.�19.6) for a non-violent non-sexual crime. This somewhat

extensive average criminal history, combined with the fact that the offences were committed

against stranger targets and included high levels of violence, indicates that this group would

consist of high-risk sex offenders. As mentioned, it was the intention of this study to examine

specifically the most ‘‘dangerous’’ subpopulation of sex offenders, and a high-risk sex offender

sample is the best way to ensure that this has been accomplished.

Procedures

An instrument was built to conduct in-depth semi-structured interviews, guided by the

theoretical principles of the rational choice perspective. The main advantage of a semi-

structured interview is that it allows participants to speak freely and at length, applying their

own concepts and discourse. Furthermore, it can be conducted in a relatively informal, non-

threatening manner, providing the opportunity to develop a relationship of trust and

confidence between researcher and participant (Bennett & Wright, 1984). Open-ended

questions were asked of the offenders about their behaviour before and during the crime-

commission process 1. Offenders were made aware of their anonymity and confidentiality and

were guaranteed that information provided during the interview could not be used against

them by the Correctional Service of Canada (CSC) 2. Interviews were conducted in a private

office, isolated from correctional staff and other inmates. The interviews lasted from 2 to 12

hours, depending on the number of crimes committed and discussed as well as how in-depth

participants wished to delve. Due to their sensitive nature, interviews were not recorded, but

extensive verbatim notes were taken.

Measures

Dependent variables. Analyses were conducted on four separate dichotomous dependent

variables. Two of these variables measured spatial aspects of the criminal event and two

measured temporal components. The first spatial dependent variable examined whether the

crime site was classified as inside or outside; of the 361 offences included in the study, 262

(73%) occurred inside (e.g. a bar, a building elevator) and 99 (27%) occurred outside (e.g. a

car park, a park). The second spatial dependent variable measured whether the crime site was

176 S. Balemba & E. Beauregard

classified as a private or public location, with 234 (65%) taking place in a private location

(e.g. victim’s residence) and 127 (35%) in a public setting (e.g. a public transportation

station).

The temporal dependent variables examined whether the offence occurred during the

day or at night, with 217 (60%) having transpired during the day and 144 (40%) at night, as

well as during the week or on the weekend, with 247 (68%) taking place during the week and

114 (32%) on the weekend 3. For any instances in which the crime was reported to have

occurred during both the day and the night, these were designated as daytime crimes, as it

seemed to be most important to distinguish those offenders who would commit their crime

during the day at all. Furthermore, in cases that crossed over so that they occurred at the

weekend as well as the weekday, these were classified as weekend crimes as it seemed that

crimes that occurred close to the weekend as well as during the weekend itself would be more

similar to weekend crimes than weekday-only crimes.

Independent variables. The independent variables that were examined were either those

pertaining to the commission of the offence itself (MO variables) or pertinent factors about

the target. The full list of the independent variables included in the study (16 MO variables

Table I. List of independent variables and their respective levels

Modus operandi variables Levels

Method to commit crime Non-coercive (39.9%)/coercive (60.1%)

Strategies to commit crime1 Non-violent (35.5%)/violent (64.5%)

Kidnap-style attack No (77.6%)/yes (22.4%)

Use of a weapon No (69.3%)/yes (30.7%)

Use of a disguise No (80.1%)/yes (19.9%)

Use of restraints No (86.1%)/yes (13.9%)

Offender broke into victim’s home No (88.1%)/yes (11.9%)

Level of force used No force (39.6%)/minimum force (41.0%)/more than necessary

(19.4%)

Type of sexual acts No penetration (48.2%)/penetration (51.8%)

Victim mutilated No (95.8%)/yes (4.2%)

Victim forced to commit sexual acts No (46.8%)/yes (53.2%)

Victim humiliated No (86.1%)/yes (13.9%)

Time spent at the scene Less than 30 min (58.0%)/30 min or longer (42.0%)

Predominant affect Sexually aroused (80.6%)/other emotion dominant (19.4%)

Physical harm done to victim2 No harm (76.7%)/harm (23.3%)

Offender forensically aware3 No (57.6%)/yes (42.4%)

Target variables Levels

Victim�offender relationship4 Stranger (66.2%)/already seen or talked to (33.8%)

Victim had characteristics searched for by

offender

No (49.9%)/yes (50.1%)

Victim dressed provocatively No (81.4%)/yes (18.6%)

Victim alone No (42.4%)/yes (57.6%)

Victim age Under 16 (42.7%)/16 or older (57.3%)

1Violent strategies included threats or physical force. 2This physical harm is in addition to the harm caused by

the rape or molestation itself. Harm included death of the victim. 3The offender was considered forensically

aware if he tried to conceal his identity, wore gloves, tried to not leave semen, prevented his face from being

seen, lied about his name, used a condom, refrained from ejaculating in or on his victim, made the victim

comb pubic hair, made the victim shower or took care of the victim’s identity (mostly relevant to cases of

sexual homicide). 4Although all the cases involved stranger victims, the victim�offender relationship variable

referred to whether any contact had been made (i.e. that day) prior to the attack itself.

Where and when? 177

and five target variables) with their corresponding levels is presented in Table I. The MO

variables are characteristics of the crime itself and consist of factors over which the offender

has direct control during the sexual assault. The offender must, therefore, make a decision

with respect to these factors while the criminal event is taking place, and these decisions are

expected to relate to spatiotemporal decisions. The target variables consisted of characteristics

of the victim that were expected to affect offender decision-making. These variables were

reported from the offender’s perspective as he observed them before committing the assault.

Thus, the study analysed whether the offender’s perception of the victim affected when and

where he decided to commit his crime.

Analytical strategy

Exhaustive chi-squared automatic interaction detection (CHAID) was performed to identify

interactions and relationships between the independent variables that affect the prediction of

each of the dependent variables. CHAID is a type of statistical technique referred to as a

decision tree, which was first devised by Kass (1980) as an extension of automatic interaction

detection (AID) with the integration of chi-square analyses of interactions. Thus, CHAID

automatically computes a series of cross-tabulations for all pairs of independent variables

(Hoare, 2004). The most significant of these cross-tabulation results are then incorporated

into a classification tree. An exploratory technique, the tree divides the data into mutually

exclusive subsets*or nodes*that exhaust all the data and are the best combination to

describe and predict the dependent variable (Kass, 1980). The ordering of each successive

split of the data is an important feature of CHAID. The top node contains all the data and the

most significant variable associated with the dependent variable determines the first split

(Hoare, 2004; Wilkinson, 1992). Each node, or group of cases, is then split sequentially based

on the significance of variables and interactions within that node. This splitting process is

continued until a stopping rule is invoked or until there are no more variables that split the

remaining cases significantly.

In the present analyses, a variation on the CHAID procedure known as exhaustive

CHAID (Biggs, De Ville, & Suen, 1991) is used. It differs slightly in its algorithm, but

optimises the selection of the appropriate variable splitting by a more thorough generation of

predictor-to-outcome comparisons. Ordinary CHAID may potentially stop testing ways to

split the sample upon discovery of a way to make all groups statistically different; exhaustive

CHAID, alternatively, continues to test all possible ways of splitting the sample until the

strongest and best predictors are elucidated (Struhl, 2002). Exhaustive CHAID was chosen as

the main procedure for these studies because of an interest in the statistical interactions

among independent variables and the prediction that these interactions will be important in

determining various spatial and temporal crime characteristics. Furthermore, the exploratory

nature of the technique is attractive, given the relatively unexplored status of the area

examining the spatiotemporal aspects of sexual offences. Separate exhaustive CHAID

analyses are conducted on each of the four dependent variables, producing four distinct

exhaustive CHAID models 4.

The predictive accuracies of each exhaustive CHAID model are tested using receiver

operating characteristic (ROC) analysis. Essentially, ROC depicts trade-offs between benefits

(true positives) and costs (false positives) of the predictability of a model (Fawcett, 2006).

The ROC also gives a measure of the area under the curve (AUC) that represents the

probability that the model will rank outcomes correctly (Fawcett, 2006). The closer the AUC

is to 1.00, the better the predictability of the model, with an AUC of .5 indicative of a model

that does not predict the dependent variable better than mere chance alone.

178 S. Balemba & E. Beauregard

Results

Inside versus outside

The results of the exhaustive CHAID analysis for the first spatial dependent variable*whether the crime occurred inside or outside*are presented in Figure 1. As discussed

within the previous section, the most significant and important variable within a CHAID tree

is always the first-split variable. In this case, whether the offender utilised a kidnap-style attack

was the most significant variable, indicating its importance when attempting to predict

whether an offence took place indoors or outdoors.

In each CHAID tree to be presented there is an overall pattern of two general pathways,

generally consistent with the two categories of the dependent variable. In this case, there is an

overall ‘‘inside’’ pathway to the left and an overall ‘‘outside’’ pathway to the right. Thus, it

seems that if the offender kidnaps his victim, the offence is most likely to occur outside

(64.2%, n�52), whereas an attack that does not involve kidnapping will probably be indoors

(83.2%, n�233). When the offender kidnaps his victim, this interacts with the victim’s age so

that an older victim will most likely be offended against outdoors (85.7%, n�48). When an

adult victim is perceived to be dressed provocatively, this coincides further with a greater risk

of an outdoor attack (100%, n�30).

When the victim is not kidnapped, this intersects with the victim�offender relationship so

that a stranger attack is less likely to take place indoors (76.1%, n�121) compared to cases

that involve a previous encounter with the victim on the day of the assault (inside: 92.6%,

n�112). Furthermore, if an offender broke into a stranger victim’s home, it was always the

case that the offence occurred indoors (probably the victim’s home after the break-in) (100%,

n�35). However, if there was no break-in (still with reference to stranger victims, however), if

the victim was alone, this then increased the likelihood of an outside offence (38.6%, n�32)

compared to cases in which the victim was not alone (outside: 14.6%, n�6), although the

offence occurred outside most frequently for both.

The classification accuracy, which determines how often the CHAID tree classified cases

correctly, was a relatively high 84%, with a commensurate AUC of .863 (pB.001). This

indicates that the CHAID model is performing fairly well in its ability to predict whether the

sex offence occurred inside or outside based on the information provided by the independent

variables.

Private versus public

The exhaustive CHAID model for the second spatial dependent variable*whether the

offence took place in a private or public location*is presented in Figure 2. In this case, the

first-split variable is the offender’s predominant affect during the crime; when sexual arousal

was dominant, the offence was more likely to occur in a private location (72.2%, n�210).

When another emotion was dominant (such as anger, guilt, sadness, fear, happiness or

confusion), this interacted with the forensic awareness of the offender so that a forensically

aware offender was even more likely to commit the crime within a public location (77.1%,

n�27). This may be due to an offender’s knowledge of other forensic or police factors,

including not wanting his victim to be able to pinpoint a private location (such as his house or

a regular hangout) that could be connected to him later.

When the predominant affect was sexual arousal and the offender broke into the victim’s

home, it was always the case that the offence occurred within a private location (again,

probably the victim’s home after the break-in) (100%, n�42). However, if there was no

break-in for a sexually aroused offender, excessive force was associated with a switch to the

Where and when? 179

Crime Site (Inside vs. Outside)Inside = 72.6%

73% 27%

Offender Broke Into Victim’s Home

YesInside = 35.8%

36% 64%

StrangerInside = 76.1%

Already Seen/Talked toInside = 92.6%

Under 16Inside = 84.0%

16 or OlderInside = 14.3%

14% 86%

YesInside = 0.0%

NoInside = 83.2%

83% 17%

NoInside = 30.8%

31% 69%

YesInside = 100%

NoInside = 69.4%

Victim Dressed Provocatively

Victim-Offender Relationship

Kidnap Style Attack

Victim Age

Victim Alone

NoInside = 85.4%

85% 15%

YesInside = 61.4%

76% 24% 93%

7%

69% 31% 100%

61% 39%

84% 16%

100%

FIGURE 1. Exhaustive chi-squared automatic interaction detection (CHAID) decision tree of the effects of modus operandi and target variables on whether the crime was committed

inside or outside.

180

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Crime Site (Private vs. Public)Private = 64.8%

65% 35%

Other EmotionPrivate = 34.3%

34% 66%

NoPrivate = 67.5%

YesPrivate = 100%

NoPrivate = 45.7%

YesPrivate = 22.9%

23% 77%

Sexually ArousedPrivate = 72.2%

72% 28%

Offender broke into victim’s home

Predominant Affect

Forensic Awareness

Level of Force Used

Minimum ForcePrivate = 80.2%

80% 20%

No ForcePrivate = 65.3%

68% 32%

65% 35%

46% 54%100%

More than NecessaryPrivate = 37.5%

38% 62%

YesPrivate = 24.1%

NoPrivate = 78.3%

78% 22%

Victim Alone

24% 76%

NoPrivate = 59.0%

YesPrivate = 94.7%

Kidnap Style Attack

59% 41% 95%

5%

FIGURE 2. Exhaustive chi-squared automatic interaction detection (CHAID) decision tree of the effects of modus operandi and target variables on whether the crime was committed

in private or public.

Where

and

when

?181

offence being more likely to occur in a public place (62.5%, n�20). However, if some force

was used, but a minimal amount, it was very likely that the offence occurred within a private

location (80.2%, n�77), and if the victim had been kidnapped this likelihood was increased

further (94.7%, n�54). However, if the offender did not use physical force, the offence was

somewhat more likely to occur in a private location than a public one (65.3%, n�79),

especially if the victim was not alone at first contact with the offender (78.3%, n�72).

However, if the victim was alone, an offender who does not use force will most likely commit

his crime in a public location (75.9%, n�22), which is probably due simply to greater ease of

subduing a victim without the use of force when she is alone. Once again, the classification

accuracy (77%) and AUC (.837, pB.001) are high enough to suggest that the CHAID model

is predicting the crime site location as private or public reasonably well.

Day versus night

The first CHAID model examining a temporal dependent variable*whether the crime

transpired during the day or at night*is depicted in Figure 3. The most important, first-split

variable when predicting this dependent variable is the age of the victim, with older victims

found to be more likely to be attacked at night (57.0%, n�118) and younger victims during

the daytime (83.1%, n �128). This coincides with the findings in the first CHAID tree

(inside versus outside) that older victims are more likely than younger victims to be victimised

while outside and dressed provocatively, which may now be connected to night-time or

evening victimisation.

When younger victims are forced to commit sexual acts on the offender, the likelihood of

the offence occurring during the day increases (91.3%, n�95). However, the likelihood for a

night-time attack increases slightly when this victim group is subjected to penetration during

the assault (17.0%, n�9), although a daytime assault remains the most probable scenario

(83.0%, n�44). The overall finding that most younger victims are victimised during the day

is consistent with this same age group having been found to be subjected to attacks that occur

within a private setting (previous CHAID model). Furthermore, children are more likely to be

offended against while indoors (as supported in the first CHAID model), which suggests that

attacks could occur against these younger victims during the day while under the cover of a

private, indoor location.

Among older victims, a lack of physical force utilisation by the offender makes the most

probable situation a daytime attack (75.6%, n�34). This is due probably to a more

manipulative strategy, which would not require the cover of darkness. However, when some

force is used this is likely to coincide with a night-time assault (78.1%, n�82), especially

when the victim possesses characteristics sought out by the offender (88.9%, n�56). When

an excessive amount of force is used, a daytime attack is somewhat more likely (56.1%,

n�32), the likelihood of which increases again when the victim is forced to commit sexual

acts on the offender (71.0%, n�22).

The classification accuracy (78%) and AUC (.839, pB.001) are still holding strong,

indicating a useful, predictive model. Incidentally, upon running a similar model testing

‘‘clear versus dark’’ as the dependent variable to account for the true difference between day

and night (i.e. visibility based on the amount of light), an almost exact replicate of this

CHAID tree was produced. Due to its similarity, it is not presented in this study, but the

replication strengthens these particular findings further.

182 S. Balemba & E. Beauregard

Time of Crime (Day vs. Night)Day = 60.1%

60% 40%

16 or OlderDay = 43.0%

43% 57%

YesDay = 91.3%

NoDay = 66.0%

No PenetrationDay = 100%

PenetrationDay = 83.0%

83% 17%

Under 16Day = 83.1%

83% 17%

Victim Forced to Commit Sexual Acts

Victim Age

Type of Sexual Acts

Level of Force Used

Minimum ForceDay = 21.9%

22% 78%

No ForceDay = 75.6%

76% 24%

More than NecessaryDay = 56.1%56% 44%

YesDay = 11.1%

NoDay = 38.1%

38% 62%

Victim Characteristics Searched for by Offender

89%

NoDay = 38.5%

YesDay = 71.0%

Victim Forced to Commit Sexual Acts

39% 61%

66% 34% 91%

9%

100% 71% 29%

FIGURE 3. Exhaustive chi-squared automatic interaction detection (CHAID) decision tree of the effects of modus operandi and target variables on whether the crime was committed during

the day or at night.

Where

and

when

?183

Week versus weekend

The final exhaustive CHAID model, classifying the second temporal dependent variable*whether the crime occurred during the week or on the weekend*is displayed in Figure 4. The

most important, first-split variable for this dependent variable is the victim�offender

relationship, with a stranger victim, who has had no previous contact with the offender,

more likely to be attacked during the week (83.7%, n�200). This most probably refers to an

overall more random attack strategy.

When the victim is a stranger, a forensically aware offender is even more likely to offend

during the week (93.2%, n�137), with the likelihood of a weekday offence increasing even

more when the predominant affect is sexual arousal (96.6%, n�112). This may be related to

the previous finding that forensically aware offenders are also more likely to offend in a public

location, as many public places are more likely to be populated during the week. Interestingly,

however, if an offender is not forensically aware, when the predominant affect is sexual

arousal, this increases the likelihood of a weekend offence (41.8%, n�28). A lack of forensic

awareness could sometimes occur when an offender does not feel as though forensic

considerations are important, most notably in cases of date rape 5. Furthermore, within the

CHAID tree, a sexually aroused offender who is not forensically aware (and who offends

against a stranger) is more likely, when the victim is older, to commit his offence during the

week (71.9%, n�23).

When the offender chooses to offend against a previously contacted victim, the offence is

more likely to occur on the weekend (61.5%, n�75), particularly if the victim is not alone

when contact is made (68.8%, n�64). The likelihood of the offence occurring on the

weekend increases further when an attack on such a victim involves penetration (96.8%,

n�30) (overall, very akin to a date rape scenario). For the final exhaustive CHAID analysis,

the classification accuracy and AUC are still fairly high, at 79% and .859 (pB.001),

respectively, indicating a valid and useful model once again.

Discussion

The results of the analyses presented herein indicate different factors relevant in the

classification of crime location and timing. In brief, the results regarding the most important,

first-split variables in each CHAID analysis suggest that: when a victim is kidnapped as part of

the crime, the offence is more likely to occur outside; sexual arousal is more likely to be the

predominant affect during an offence committed in private; the offence is more likely to occur

at night when the victim is an adult (this held true when the variable was changed to clear

versus dark as opposed to night versus day); and the crime is more likely to happen on a

weekday when the victim is a stranger. Thus, there were many indications within the

exhaustive CHAID analyses of crime type differences. In order to illustrate these differences,

short, hypothetical case studies incorporating variables determined to be significant predictors

of where and when the crime occurs are presented in the discussion of each pathway.

Our findings show that a sexual crime is more likely to take place outdoors when the

victim is kidnapped and when the victim is an adult dressed provocatively (according to the

offender). For instance, a man is walking down the street and sees a woman in her early 30s.

He perceives her to be dressed very provocatively. He grabs her as she is walking by and drags

her to a nearby park where he rapes her. However, an indoor crime is more likely to result

from an attack that does not involve kidnapping, the likelihood increasing even more when the

victim has already been seen by or has talked to the offender. The crime is also more likely to

take place indoors when the offender breaks into the victim’s home or, if there is no break-in,

184 S. Balemba & E. Beauregard

Time of Crime (Week vs. Weekend)Week = 68.4%

68% 32%

Predominant Affect

Already seen/Talked toWeek = 38.5%

39% 61%

YesWeek = 93.2%

YesWeek = 62.1%

NoWeek = 31.2%

31% 69%

PenetrationWeek = 3.2%

StrangerWeek = 83.7%

84% 16%

No PenetrationWeek = 45.2%45% 55%

Other EmotionWeek = 96.0%

Sexually ArousedWeek = 58.2%

Type of Sexual Acts

Forensic Awareness

Victim-Offender Relationship

Victim Alone

Victim Age

16 or OlderWeek = 71.9%

72% 28%

Under 16Week = 45.7%

93%

7%

58% 42% 96%

4%

46% 54%

62% 38%

97

3%

%

69% 31%

NoWeek = 68.5%

Predominant Affect

Other EmotionWeek = 80.6%

Sexually ArousedWeek = 96.6%

81% 19%97%

3%

FIGURE 4. Exhaustive chi-squared automatic interaction detection (CHAID) decision tree of the effects of modus operandi and target variables on whether the crime was committed during

the week or at the weekend.

Where

and

when

?185

if the victim is not alone at the time of first contact with the offender. For instance, an offender

may have seen the victim enter her house or followed her home from another location. Upon

breaking into her home successfully, he forces her into the bedroom and sexually assaults her.

An offence is most likely to occur in a private location when the offender is sexually

aroused and the offender breaks into the victim’s home. If the offender did not break in, a

minimum level of force, combined with a kidnap-style attack, results in a high likelihood of

the crime taking place in a private location. The following example illustrates these results. A

man attends a house party, having been invited in by an intoxicated partygoer. He meets a

woman among the crowd and becomes sexually aroused by her flirtation. He offers her a

drink, which he had dosed with RohypnolTM 6. Once she drinks it and begins to lose

consciousness, the assailant leads her into a nearby bedroom and, without the need for force,

rapes her. In the case where a non-sexual emotion dominates the assault and the offender is

forensically aware, the offence is most likely to have occurred in a public venue. For instance,

an offender is walking through a public park, in an angry mood and just wanting to cause

some pain. He sees a woman and, directing all his anger towards her, pre-emptively slips on a

condom and then forces himself on her, pulling her shirt over her face so that she cannot see

him.

With respect to time of day, an attack during daytime will most probably be committed

against a child and involve forced victim participation, but no penetration. For example, a

young girl of 10 years is lured into a man’s home on a sunny afternoon, where the two begin to

play games. The man slowly directs the play to become increasingly sexual until he begins to

fondle her, although without penetration. He then instructs her to touch him as well and the

girl complies. Alternatively, an assault during the night will more probably be against an adult

victim who possesses characteristics searched for by the offender and involve minimal force.

As an example, a woman in her 20s is leaving a nightclub when an offender notices her. He

finds her very attractive and is especially appreciative of her slender build and dark features,

attributes that he often seeks out in a partner. The offender strikes up a conversation with her

and leads her down a dark alley. When she resists his advances, he uses just enough force

necessary to subdue her and completes the assault.

Lastly, a sexual crime that takes place on a weekday will most likely involve a complete

stranger victim, and the offender will present with some degree of forensic awareness, with

sexual arousal predominant although, if the offender is not forensically aware, some other

emotion is likely to dominate. As an example, an offender encounters a woman he has never

seen before on the subway during the workday rush hour. He becomes sexually aroused when

she is forced accidentally to rub up against him on the crowded train. He follows her off of the

train and lures her aside by asking for directions, introducing himself using a false name. Once

out of sight of other passengers, he fondles her and then runs away. Alternatively, a weekend

offence will probably be perpetrated against a victim who has already been in contact with the

offender and will be instigated when she is not alone, probably involving penetration. To

illustrate, an offender meets a victim in a bar on a Saturday night. He flirts with her and they

dance together with some of her friends. Later into the evening, he notices that she is even

more intoxicated and decides to take advantage of the situation. He leads her into the

bathroom and rapes her with penetration.

These divergent results tap into the variations in offender decision-making within diverse

crime types, when these types are defined by locational and temporal factors. Thus, an

offender is more likely to let his sexual arousal lead him to offend while in a private setting, but

when choosing when to attack a victim this may depend more on opportunity and target

variables, such as what types of victims the offender is more likely to interact with during the

time of day or week in question.

186 S. Balemba & E. Beauregard

One of the main points to be taken from the analyses as a whole is that, overall, the results

were strikingly different dependent on which spatial or temporal aspect of the crime was

examined. This further implies the complexity of sexual events and their situational

components as well as emphasises the need to develop and conduct further research on

these various aspects of the criminal event.

Implications: Situational crime prevention

This research brings to light possible policy implications with respect to situational crime

prevention that could be targeted towards specific types of sex offences. For situational crime

prevention to be most effective, specific crime types must be targeted, which requires

knowledge of such criminal events. Thus, the present research has elucidated certain aspects

that are associated with indoor versus outdoor or private versus public crimes, as well as

distinguishing factors related to time of day or week when offences occur. Both spatial and

temporal aspects could inform situational crime prevention efforts in order to direct resources

more narrowly and effectively for a greater effect on crime prevention. For example, police

could direct more patrols intentionally where older potential victims may congregate outside

at night, with more focused patrols on weekends.

The current results are not sufficient alone to suggest or implement specific situational

crime prevention initiatives. Rather, they have the potential to be instrumental in informing

situational prevention methods in where and when particular methods would best be applied.

For example, suggestions offered by Smallbone and colleagues (2008) with respect to

situational prevention of child sexual abuse could be directed even more specifically to the

time and place when these strategies would be most effective. Although the current study

could only offer improvements to the situational prevention methods directed at crimes that

occur or are initiated in a public setting (due to the specification of stranger attacks within the

tested sample), these could include suggestions such as directing extended guardianship (via

direct supervision of children by parents or employees within the area) to take place especially

on weekdays, when children are most vulnerable to attack, and being especially vigilant to

invitations to an indoor, private location by strangers. Prevention resources such as these are

often spread thinly over vast potential offending locations and may not be able to be

operational at all times; thus, determining when and where they are more or less necessary is a

way to learn how to allocate these resources most effectively. No situational prevention

strategy will eliminate completely the danger to children or other vulnerable targets; however,

better direction with respect to when and where potential victims are most at risk can help to

increase the effectiveness of these strategies, maximising the reduction in offending.

A key asset of the methodology of the current study to its usefulness in situational crime

prevention efforts is the fact that the data arise from offender interviews. Thus, all the

information derived herein is not what police or policy-makers or even victims believe causes

the observed spatiotemporal patterns; it is what the offenders perceived at the time of their

offence. As discussed previously, situational crime prevention must be designed based on

offender perceptions. If policies are enacted and preventative measures created that are based

on the wrong source of data, those will be much less effectual than policies and measures that

have arisen from offender reports. Although others may believe that streetlights in a given area

will reduce attacks on children, but such offences are more likely to happen during the day

anyway, the lights will not have the desired reduction effect on child victimisation. However, if

society uses offenders as rich sources of information from whom to learn why criminals

choose to offend in a particular area at a particular time, then real prevention may begin to be

seen. The current study has taken advantage of the perceptions that truly matter when

Where and when? 187

deciphering why crimes happen where and when they do: those of the people who actually

make those decisions.

There have been some criticisms of situational crime prevention, most notably those

which state that this type of prevention simply results in displacement of crime rather than a

decrease in the behaviour. Displacement has been purported to occur with respect to place,

time, target, crime type or tactic (or any combination of these; Reppetto, 1976; Tilley, 2009).

However, empirical analyses have generally determined that fears of displacement are

exaggerated or unwarranted (Guerette & Bowers, 2009; Hesseling, 1994; Reppetto, 1976).

Rather, the opposite effect, diffusion of benefits, is more often encountered when situational

prevention measures are implemented (Guerette & Bowers, 2009; Tilley, 2009). If, for

example, hedges are trimmed and streetlights installed to increase visibility and, thereby,

decrease stranger rapes and assaults in a particularly dangerous area of a public park, a

subsequent decrease in crime will often occur, not only in that particular area, but also within

the surrounding park. Such a diffusion of benefits may, potentially, occur in conjunction with

some displacement; however, in general, the net effect of situational crime prevention

measures usually results in an overall decrease in the targeted criminal behaviour (Guerette &

Bowers, 2009; Tilley, 2009).

The merits of situational crime prevention are undeniable; a crime simply cannot

continue to take place if the opportunity is stripped away. However, to create valid, useful

situational prevention techniques, the crimes themselves must be analysed to reveal the

factors associated with their occurrence*a task the current study has begun to address.

Specifically, the situational and environmental components surrounding and intrinsic to the

commission of a sexual crime have begun to be elucidated; such a process is a necessary first

step before maximally effective situational crime prevention methods can follow.

Conclusion

The results of the current study, although complex, have introduced relationships between

MO, target preferences and the criminology of time and place. A great deal of information has

been unearthed related to offender decision-making that culminates in a sexual assault,

specifically what related decisions result in where and when the crime occurs. However, this

study is not without limitations. Although also viewed as one of the major strengths, given the

focus of the analyses, one of the most important limitations is the fact that the participants

were all serial sex offenders who assaulted stranger victims, which could have possibly

increased the likelihood of detecting patterns between offences committed by the same

offender. However, as most crimes are committed by serial offenders (Rossmo, 2000), crimes

committed by the same individual cannot be separated or removed without sacrificing realism

and practicality within interpretations of the results. This limitation also potentially makes it

difficult to generalise the findings to all sex offenders, although this was not necessarily the

goal of this research. Moreover, potential bias may have arisen due to the retrospective and

self-reported nature of the data. It is possible that the reported decisions and event

characteristics disclosed by sex offenders after the fact differs from decisions and behaviour

that happen at the moment of the crime itself. However, other methods, such as using

hypothetical scenarios, suffer their own limitations as well (Exum & Bouffard, 2010). The

offenders themselves represent one of the best available sources of information about the

commission of their own crimes. Thus, the use of offender reports, although limited to a

certain extent, is more than justified, especially given the purpose of the current study.

188 S. Balemba & E. Beauregard

The analyses presented focus on the criminal event, choosing to avoid delving into

individual motivational factors. Although individual factors are important, this should not

diminish the importance of situational factors in the commission of sexual crimes. Others

have also demonstrated the relevance and promise of moving from a prevention approach

based on offender treatment to situational crime prevention strategies (Wortley & Smallbone,

2006). However, although focused on the criminal event, the current study also examines

serial offenders specifically, thus interspersing the notion of MO, which may develop

predictable patterns over time in serial offenders, although patterns that are certainly affected

by context and situational factors (Beauregard, Proulx, Rossmo, Leclerc, & Allaire, 2007;

Beauregard, Rossmo, & Proulx, 2007).

This research has examined the situational factors relevant to the where and when of

crimes committed by prolific sex offender recidivists. It is imperative to understand such

crimes as deeply as possible, both for public safety as well as research and policy development.

While most criminals are not serial in nature, most crime is, because a high proportion of

offences are committed by a small proportion of offenders (Rossmo, 2000). Thus, to

understand and potentially be able to prevent the most crime requires a complete

comprehension of the decisions that serial offenders make when committing a crime. Where

and when these crimes take place are among the most important considerations that have

received all too little research attention. This study is an attempt to fill some of this existing

gap in order to inform policy and, perchance, affect the direction of future research.

Acknowledgements

This research was supported by the Social Sciences and Humanities Research Council.

Notes

1. As part of the semi-structured interview, the researcher would ask the offender to describe how the crime was

committed as an open-ended question. Then, after taking notes on the answers provided by the offender, follow-up

questions would be asked to get to specific details. For example: ‘‘Did you use a weapon? If yes, why? If not, then

why not?’’. Another example is related to the sexual acts committed between the offender and the victim. The

researcher would ask the offender to describe the sexual acts that were committed during the sexual assault. Then,

after noting all the details provided by the offender, subsequent questions could follow in order to gain more details

on the sexual acts committed. For instance, ‘‘did you penetrate the victim with your penis?’’.

2. Inmates were told, however, that, if they disclosed impending harm to themselves or others, the proper authorities

would be notified.

3. Both the week/weekend and inside/outside variables have been examined under similar dichotomies in previous

spatiotemporal sex offender literature (Canter & Gregory, 1994).

4. Each exhaustive CHAID model included all 361 sexual crimes.

5. References to ‘‘date rape’’ within the discussion of the results do not refer to date rape within any perceivable

relationship (as all of the victims were strangers to the offender prior to the day of the assault) but, rather, an

encounter that begins as consensual, perhaps flirtatious behaviour, but then changes into aggressive, assaultive

behaviour when the victim tries to stop or slow down the offender’s physical advances.

6. RohypnolTM (clinical name: Flunitrazepam) is a sedative�hypnotic benzodiazepine that causes profound sedation

and memory loss as well as reducing the will to resist sexual advances (Schwartz & Weaver, 1998). It is commonly

referred to as the ‘‘date rape drug’’.

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