Quantitative and Quantitative and Qualitative MethodsQualitative Methods

MHE3 – Research Methods 4MHE3 – Research Methods 4

Affette McCaw-BinnsAffette McCaw-Binns

Community Health SectionCommunity Health Section

Learning ObjectivesLearning Objectives

Distinguish between qualitative and Distinguish between qualitative and quantitative methods of data quantitative methods of data collectioncollection

Describe four sampling methods for Describe four sampling methods for collecting quantitative data collecting quantitative data

Describe three types of qualitative Describe three types of qualitative research methodsresearch methods

Compare and contrast uses of Compare and contrast uses of qualitative and quantitative dataqualitative and quantitative data

Quantitative data collection Quantitative data collection methodsmethods

Census – full count of total Census – full count of total populationpopulation

Survey – sample of populationSurvey – sample of populationStudy units selected from the Study units selected from the populationpopulation

in such a way that the findings can be in such a way that the findings can be generalized to the general populationgeneralized to the general population

RepresentativenessRepresentativeness

IfIf researchers researchers →→ conclusions that are conclusions that are validvalid for the study population for the study population

TheTheyy must draw a sample that it is must draw a sample that it is representative representative of that populationof that population

A A representative samplerepresentative sample has all the has all the characteristicscharacteristics of the population from of the population from which it is drawnwhich it is drawn

SamplingSampling

Population – group of people, Population – group of people, institutions, cases or objects defined institutions, cases or objects defined as under study by a researcheras under study by a researchere.g. people, hospitals, batse.g. people, hospitals, bats

Sample population – group on whom Sample population – group on whom data are collecteddata are collectedPopulation – pregnant women in JamaicaPopulation – pregnant women in JamaicaSample population – pregnant women in Sample population – pregnant women in

KSAKSA

Types of samplesTypes of samples

Non-probability Non-probability –– sample chosen in a sample chosen in a haphazard fashionhaphazard fashion convenience convenience quotaquota snowballsnowball

Probability Probability –– each individual unit in the total each individual unit in the total population has a known probability of being population has a known probability of being selectedselected simple random simple random systematic systematic stratifiedstratified clustercluster

Convenience samplingConvenience sampling

Study units selected because they are Study units selected because they are available at the time of data collectionavailable at the time of data collection

e.g. standing in Liguanea and asking e.g. standing in Liguanea and asking questionsquestions

Drawback:Drawback: Sample may not be representative Sample may not be representative Some units may be over-selected, other Some units may be over-selected, other

under-selected or missed altogetherunder-selected or missed altogether Impossible to adjust for such a distortionImpossible to adjust for such a distortion

Quota samplingQuota sampling Sample units selected so that all categories of a Sample units selected so that all categories of a

specific characteristic is representedspecific characteristic is represented

Quotas – chosen to represent the distribution of Quotas – chosen to represent the distribution of these characteristics in the parent population, e.g.these characteristics in the parent population, e.g.

Age – 55% young, 40% middle age, 10% old Age – 55% young, 40% middle age, 10% old Gender – 48% male, 52% femaleGender – 48% male, 52% female

Interview as many people in each category until Interview as many people in each category until fill the quota for characteristic of interestfill the quota for characteristic of interest

Drawback:Drawback: May not be representative of the May not be representative of the populationpopulation Some groups not representedSome groups not represented Some groups over-representedSome groups over-represented

Snowball samplingSnowball sampling

People who meet study’s inclusion People who meet study’s inclusion criteria are asked to name others criteria are asked to name others who meet the criteriawho meet the criteria

Useful to identify hard-to-find Useful to identify hard-to-find individualsindividuals e.g. persons with deviant or illegal e.g. persons with deviant or illegal

behaviour (MSM, CSWs)behaviour (MSM, CSWs)Sample may not be representativeSample may not be representative

Simple random sampleSimple random sample

Each sampling unit has the same Each sampling unit has the same probability of being selectedprobability of being selectedChance alone decides which individual Chance alone decides which individual

units in the parent population will be units in the parent population will be selectedselected

RequirementRequirementSampling frame = Sampling frame = listing of all study listing of all study

units needs to exist or can be compiledunits needs to exist or can be compiled

Procedure – simple random Procedure – simple random samplesample

Identify sampling frame, e.g.Identify sampling frame, e.g. Voters listVoters list Census populationCensus population Health centre register etc.Health centre register etc.

Decide on the sample sizeDecide on the sample size Select required number of sampling Select required number of sampling

units, using:units, using: Lottery method (‘grab bag’)Lottery method (‘grab bag’) Table of random numbersTable of random numbers

Systematic sample ISystematic sample I

Individuals chosen at regular intervals (e.g. Individuals chosen at regular intervals (e.g. every 5th) from the sampling frameevery 5th) from the sampling frame

ProcessProcess:: Decide sampling fraction (e.g. 5%)Decide sampling fraction (e.g. 5%) List the population in order List the population in order Randomly select starting point based on the Randomly select starting point based on the

sampling fraction (e.g. number between 1 and sampling fraction (e.g. number between 1 and 20)20)

Start at or near the beginning of list and select Start at or near the beginning of list and select every nth person (e.g. 20every nth person (e.g. 20thth) based on the ) based on the sampling fractionsampling fraction

Systematic sampling IISystematic sampling II

AdvantagesAdvantages:: Less time consumingLess time consuming Easier to performEasier to perform Doesn’t require sampling frame ahead of timeDoesn’t require sampling frame ahead of time

e.g. persons registering at hospital on a given daye.g. persons registering at hospital on a given day

DDisadvantageisadvantage:: Risk of bias if the sampling interval coincides Risk of bias if the sampling interval coincides

with systematic variation in the sampling framewith systematic variation in the sampling frame e.g. selecting days and choosing an interval of 7e.g. selecting days and choosing an interval of 7

Stratified sampling IStratified sampling I

Simple random sampling does not Simple random sampling does not ensure that the proportion of ensure that the proportion of individuals with certain characteristics individuals with certain characteristics in the sample will be the same as in the in the sample will be the same as in the population, e.g.population, e.g.

Sample may yield 40% males, 60% Sample may yield 40% males, 60% femalesfemales

Population=48% males, 52% femalesPopulation=48% males, 52% females

Odd variations can occur by chanceOdd variations can occur by chance

Stratified sampling IIStratified sampling II Stratified random sampling adjust for thisStratified random sampling adjust for this

Reason to use: – ensures equal Reason to use: – ensures equal representation of characteristic which may representation of characteristic which may be unevenly distributed within a populationbe unevenly distributed within a population

e.g. age, sex, SES, other attributee.g. age, sex, SES, other attribute

Advantage:Advantage: Ensures that the proportion of individuals with Ensures that the proportion of individuals with

the characteristic of interest in the sample will the characteristic of interest in the sample will be the same as in the populationbe the same as in the population

Stratified sampling IIIStratified sampling III

Process:Process: Divide population into Divide population into strata strata or subsets or subsets

(based on characteristic of interest; e.g. sex)(based on characteristic of interest; e.g. sex)

DrawDraw Random sample or Random sample or Systematic sample from each subgroup orSystematic sample from each subgroup or strata strata

ifif random sample = stratified random sample random sample = stratified random sample ifif systematic sample = stratified systematic systematic sample = stratified systematic

samplesample

May have to ‘over’ sample in sparsely May have to ‘over’ sample in sparsely populated strata to have enough subjects to populated strata to have enough subjects to studystudy

Cluster Sampling ICluster Sampling I If If difficult to draw a simple random sample, e.g.difficult to draw a simple random sample, e.g.

No complete sampling frameNo complete sampling frame Logistically the process may be unwieldyLogistically the process may be unwieldy

e.g. Persons scattered over wide geographic areae.g. Persons scattered over wide geographic area

And, And, there exists a list of groupings of study there exists a list of groupings of study unitsunits

e.g. villages, schools, polling divisionse.g. villages, schools, polling divisions

Then,Then, a number of these groupings can be a number of these groupings can be randomly selectedrandomly selected

Each unit = Each unit = group of persons or unitsgroup of persons or units = cluster = cluster

Cluster sampling IICluster sampling IIProcessProcess Divide population into sub-groups or Divide population into sub-groups or clustersclusters

Not necessarily homogeneous as strata areNot necessarily homogeneous as strata are e.g. polling divisions, schoolse.g. polling divisions, schools

Draw a random sample of clustersDraw a random sample of clusters

Then, select eitherThen, select either All persons in clusterAll persons in cluster Random sample of persons in each clusterRandom sample of persons in each cluster Only persons meeting pre-identified criteriaOnly persons meeting pre-identified criteria

e.g. households with children 0-4 yearse.g. households with children 0-4 years

Each cluster = persons/units in a geographic Each cluster = persons/units in a geographic areaarea

Cluster sampling IIICluster sampling III

AdvantagesAdvantages Useful for national surveysUseful for national surveys Less expensive, time consumingLess expensive, time consuming

DisadvantagesDisadvantages May have errors if the disease, attribute May have errors if the disease, attribute

or variable being studied is itself or variable being studied is itself clustered in the population, e.g. typhoidclustered in the population, e.g. typhoid

Need an initial survey to establish if there Need an initial survey to establish if there is clustering before using the methodis clustering before using the method

Qualitative MethodsQualitative Methods

In-depth interviewsIn-depth interviews

Focus group discussionsFocus group discussions

Consensus methodsConsensus methods

QualitativeQualitative research: what is research: what is it?it?

An approach/attitude to data gathering An approach/attitude to data gathering using iusing in-depth investigation of n-depth investigation of human human perceptionsperceptions, , attitudes attitudes and and experiencesexperiences aimed at uaimed at understanding motivation and nderstanding motivation and behaviourbehaviour

Method:Method:Observations/analyses which Observations/analyses which subjectivelysubjectively

measure people’s introspection and measure people’s introspection and interpersonal interactionsinterpersonal interactions

Reporting:Reporting:Heavily supported by verbal and visual Heavily supported by verbal and visual

descriptions, quotations, and interpretive descriptions, quotations, and interpretive codingcoding

QuantiQuantitative vs tative vs QualiQualitativetative MethodsMethods

Quantitative methods – document the Quantitative methods – document the extent of the problemextent of the problemHow much of a problem is there?How much of a problem is there?Who is affected?Who is affected?

QualitativeQualitative methods – classify phenomena methods – classify phenomenaWhat is the nature of the problem as What is the nature of the problem as

people perceive it?people perceive it?Why are there differences between groups?Why are there differences between groups?What social/behavioural problems influence What social/behavioural problems influence

diseases and how?diseases and how?

Uses of Qualitative Research Uses of Qualitative Research II

Qualitative and quantitative methods Qualitative and quantitative methods increasingly being used to increasingly being used to complement each other, e.g.: complement each other, e.g.: Preliminary step to quantitative researchPreliminary step to quantitative researchClarify open ended questionsClarify open ended questionsDevelop hypothesesDevelop hypotheses

Validate quantitative researchValidate quantitative research

Uses of Qualitative Uses of Qualitative ResearchResearch IIII

Objective:Objective: Uncover reasons for variations among social Uncover reasons for variations among social

or ethnic groupsor ethnic groups Uncover social processesUncover social processes Access areas of social life not open to or Access areas of social life not open to or

amenable to quantitative researchamenable to quantitative research Evaluate changes/views re health service Evaluate changes/views re health service

provision from the viewpoint of patients, provision from the viewpoint of patients, health professionals and managers health professionals and managers

TechniquesTechniques

Direct observationDirect observation InterviewsInterviews Analysis of texts or recorded speech and Analysis of texts or recorded speech and

behaviourbehaviour Several types of qualitative research Several types of qualitative research

techniques, only three will be discussed, techniques, only three will be discussed, vizviz:: In-depth interviewIn-depth interviewFocus groups discussions andFocus groups discussions andNominal group techniqueNominal group technique

Qualitative InterviewsQualitative InterviewsTypes of questionsTypes of questions

Behaviour or experienceBehaviour or experienceOpinion or beliefOpinion or beliefFeelingsFeelingsKnowledgeKnowledgeSensory perceptionsSensory perceptions

1a.1a. Depth interviewDepth interview Definition:Definition:

Two persons discuss issue(s) with the Two persons discuss issue(s) with the understanding that there will be complete understanding that there will be complete honesty, openness, mutual trust, limited honesty, openness, mutual trust, limited interference, minimal limitations on time, and interference, minimal limitations on time, and regard for confidentiality of disclosureregard for confidentiality of disclosure

Requirement:Requirement:Absence of other participantsAbsence of other participants

Uses: Uses: Case studiesCase studiesLife history assessmentsLife history assessmentsResearch on sensitive issuesResearch on sensitive issues

Depth InterviewsDepth Interviews

Less structuredLess structured May cover only one or two issues, but in May cover only one or two issues, but in

much greater detail, e.g.much greater detail, e.g. ““This study is about how people think about This study is about how people think about

their own healththeir own health ““Can you tell me about your own health Can you tell me about your own health

experiences?experiences? Further questions would be based on what Further questions would be based on what

the interviewee said, and would consist the interviewee said, and would consist mostly of clarification and probing for detailsmostly of clarification and probing for details

1b.1b. Semi-structured Semi-structured interviewinterview

A loose structure of open ended A loose structure of open ended questions that defines the area to be questions that defines the area to be exploredexplored

Interviewer/interviewee may diverge Interviewer/interviewee may diverge from schedule to pursue issues, seek from schedule to pursue issues, seek greater detail, e.g.greater detail, e.g. “ “What do you think good health is?”What do you think good health is?” “ “How do you consider your own How do you consider your own

health?”health?”

2.2. Focus group discussionFocus group discussion

Group interview that capitalises on Group interview that capitalises on communication between participants to communication between participants to generate datagenerate data

Quick, convenient way to collect data from Quick, convenient way to collect data from several people simultaneouslyseveral people simultaneously

Uses group interaction to provide distinctive Uses group interaction to provide distinctive types of datatypes of data

People encouraged to talk to one anotherPeople encouraged to talk to one anotherAsk questionsAsk questionsExchange anecdotesExchange anecdotesComment on each others experiences/points of viewComment on each others experiences/points of view

Interactions between Interactions between participants used to:participants used to:

Individual Individual Highlight attitudes, priorities, Highlight attitudes, priorities,

framework of understandingframework of understandingFacilitate expression of Facilitate expression of

ideas/experiences that might be left ideas/experiences that might be left underdeveloped in an interviewunderdeveloped in an interview

Encourage participants to generate Encourage participants to generate and explore their own questions and and explore their own questions and develop their own analysis of develop their own analysis of common experiencescommon experiences

Interactions between Interactions between participants used to:participants used to:

GroupGroup Identify group norms/cultural valuesIdentify group norms/cultural values Illuminate participants’ perspective Illuminate participants’ perspective

through debate within the group through debate within the group Provide insight into the operation of Provide insight into the operation of

group social processes group social processes Encourage open conversation about Encourage open conversation about

embarrassing subjectsembarrassing subjectsPermit expression of criticismPermit expression of criticism

Potential advantages of focus Potential advantages of focus groupsgroups

Doesn’t discriminate against persons who Doesn’t discriminate against persons who cannot read or writecannot read or write

Facilitator can encourage participation from Facilitator can encourage participation from persons who are reluctant to be interviewed persons who are reluctant to be interviewed e.g.e.g. Intimidated by the formality and isolation of a Intimidated by the formality and isolation of a

one-to-one interviewone-to-one interview Can encourage contributions from people who Can encourage contributions from people who

feel they have ‘nothing to say’ but who feel they have ‘nothing to say’ but who engage in discussion generated by group engage in discussion generated by group membersmembers

3.3. Consensus methodsConsensus methods

Where unanimity of opinion doesn’t exist due Where unanimity of opinion doesn’t exist due to:to:Lack of scientific evidenceLack of scientific evidenceContradictory evidenceContradictory evidence

Consensus methods can be used to:Consensus methods can be used to:Assess extent of agreement (consensus Assess extent of agreement (consensus

measurement)measurement)Resolve disagreement (consensus development)Resolve disagreement (consensus development)Consider evidence from a wider range of study Consider evidence from a wider range of study

types than statistical reviews such as meta-types than statistical reviews such as meta-analysesanalyses

Allow for qualitative assessment of evidenceAllow for qualitative assessment of evidence

Features of consensus methodsFeatures of consensus methods

FeatureFeature CharacteristicsCharacteristics

AnonymityAnonymity To avoid dominance; use To avoid dominance; use questionnaire or private rankingquestionnaire or private ranking

IterationIteration Process occurs in ‘rounds’, Process occurs in ‘rounds’, allowing individuals to change allowing individuals to change their opinionstheir opinions

Controlled Controlled feedbackfeedback

Show the distribution of the Show the distribution of the group’s responsegroup’s response

Statistical Statistical group group responseresponse

Express judgement using summary Express judgement using summary measures of the full group measures of the full group responseresponse

Nominal group Nominal group technique:technique:

a.k.a. Expert panela.k.a. Expert panel Informed panel considers a problemInformed panel considers a problem

Consensus methods structured to Consensus methods structured to prevent the dominance by one prevent the dominance by one individual or vested interest groupindividual or vested interest group

Nominal group technique INominal group technique I

Series of items or questionsSeries of items or questionsUsed to examine for example:Used to examine for example:

Appropriateness of clinical interventionsAppropriateness of clinical interventionsEducation/training in practice Education/training in practice

developmentdevelopmentIdentifying measures for clinical Identifying measures for clinical

trials/other researchtrials/other researchIdentify health care/policy prioritiesIdentify health care/policy priorities

Nominal group technique Nominal group technique IIII

Highly structured meeting to gather Highly structured meeting to gather information from relevant experts (9-12)information from relevant experts (9-12)

Two rounds in which panelistsTwo rounds in which panelistsRate problem/issueRate problem/issueDiscussDiscussRe-rateRe-rate

Facilitator = expert or credible non-Facilitator = expert or credible non-expertexpert

Review of relevant literature provided to Review of relevant literature provided to participants before the meetingparticipants before the meeting

Issues: Qualitative Issues: Qualitative methodsmethods

Internal and external validityInternal and external validity Can findings from a select group be replicated?Can findings from a select group be replicated? Can they be generalised to the population?Can they be generalised to the population?

Social phenomena may be profoundly Social phenomena may be profoundly affected by the participantsaffected by the participants Did one or a few person(s) sway group opinion?Did one or a few person(s) sway group opinion? What is true in one social setting may not hold What is true in one social setting may not hold

in anotherin another

Integrating quantitative Integrating quantitative and qualitative methodsand qualitative methods

Used jointly = powerful toolsUsed jointly = powerful toolsPreliminary studiesPreliminary studies

Fact finding process to inform quantitative Fact finding process to inform quantitative researchresearche.g. Identify questions to ask re satisfaction with e.g. Identify questions to ask re satisfaction with

h. svcesh. svces

Post hoc studiesPost hoc studiesExplain unusual quantitative findings, e.g.Explain unusual quantitative findings, e.g.

Divergence between knowledge and practiceDivergence between knowledge and practice

Applications in health care Applications in health care deliverydelivery

Quantitative researchQuantitative researchTechnicalTechnicalProvides mechanisms to predict and Provides mechanisms to predict and

control specific health related variables, control specific health related variables, e.g.e.g.Causes and progress of diseases/disabilitiesCauses and progress of diseases/disabilitiesDeveloping/validating assessment Developing/validating assessment

procedures procedures Evaluating effectiveness of interventionEvaluating effectiveness of intervention

Applications in health care Applications in health care deliverydelivery

QualitativeQualitative research researchHelp us better understand our clients as Help us better understand our clients as

human beings, e.g.human beings, e.g.How illnesses/disability/health care delivery How illnesses/disability/health care delivery

affects people’s lives interpreted from their point affects people’s lives interpreted from their point of viewof view

Understand cultural differences between health Understand cultural differences between health workers and clientsworkers and clients

How patients view their bodiesHow patients view their bodies Why people behave contrary to their ‘better’ Why people behave contrary to their ‘better’

knowledge knowledge Evaluate the effects of health care environmentsEvaluate the effects of health care environments

Being in hospital; living with chronic diseasesBeing in hospital; living with chronic diseases