Research Methods & Study Design

What is research??

• A search for knowledge• An art of scientific investigation• An academic activity and as such the term

should be used in a technical sense.

RESEARCH APPROACHES

Many research projects combine anumber of approaches, e.g. may

use both quantitative andqualitative approaches

Quantitative research• The emphasis of Quantitative research is on

collecting and analysing numerical data; it concentrates on measuring the scale, range, frequency etc.

Comparison: Quantitative vs. Qualitative Research:

Quantitative Methods: – Formulate hypothesis– Observe events/present

questionnaire with fixed answers.

– Tabulate responses– Summarize data – Analyze and draw– conclusions

Qualitative Methods: – Observe events and/or ask

questions with open-ended answers.

– Record observations– Interpret observations– Return for new and refined

observations – Review data and draw

conclusions – Formulate hypothesis or

theory

Qualitative research

• Qualitative research is more subjective in nature than Quantitative research and involves examining and reflecting on the less tangible aspects of a research subject, e.g. values, attitude, perceptions.

Determining the Research Approach Use quantitative if your

research problem requires you to

• Measure Variables • Assess the impact of these

variables on an outcome • Test existing theories or

broad explanations • Apply results to a large

number of people

Use qualitative if your research problem requires

you to • Learn about the views of

the people you plan to study

• Assess a process over time• Generate theories based on

participant perspectives • Obtain detailed information

about a few people or research sites.

Type of Study Design

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Two factors characterized a study design:

i. Time

ii. Intervention

Time Perspectives• Cross-sectional

– Only look at present situation

• Retrospective– Describe events in the past– To relate a present condition to a factor that

took place in the past

• Prospective– Study objects are followed over time

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Study Design

Non-intervention

Exploratory

Descriptive

Analytical / Comparative

Case-control

Cohort

Intervention

Experimental

Quasi-experimental

Study Design Categories

Types of Study Design

• Descriptive• Case-Control• Cohort• Experimental• Quasi-experimental

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Study Design

Non-intervention

Exploratory

Descriptive

Analytical / Comparative

Case-control

Cohort

Intervention

Experimental

Quasi-experimental

Study Design

Study Design

• Exploratory studies

is a small-scale study of relatively short duration, which is carried out when little is known about a situation or a problem.

It may include description as well as comparison.

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Study Design

• Descriptive studies involves describing the characteristics of a

particular situation, event or case.

to answer WHAT , WHERE, WHEN and HOW

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Descriptive• Involves the systematic collection and

presentation of data to give a clear picture of a particular situation

• Aims at defining “what is the problem?” and seek to explore and identify various factors associated with the problem.

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Derives:

•Prevalence rates

•Association between variables

Descriptive

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Advantages• Relatively cheap to

conduct

• Relatively quick to carry out

Disadvantages• Captures the situation at

only one point in time• Unable to show causal relationship

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Descriptive

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DIRECT CAUSAL RELATIONSHIP

INDIRECT CAUSAL RELATIONSHIP

COMPLEX CAUSAL MODEL

SEX

SEX

SEX

INCOME LEVEL

INCOME LEVEL

INCOME LEVEL

EDUCATION LEVEL OCCUPATION

EDUCATION LEVEL OCCUPATION

FAMILY RESPONSBILITY

PART TIME WORK

Examples:•Nutritional Study

•Prevalence of TB with AIDS

•National Health and Morbidity Survey 3 (NHMS3)

•Qualitative Study – research using Focused Group Discussion (FGD)

•Study of young people's awareness with tobacco marketing

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Descriptive

Study Design

• Comparative or analytical studies An analytical study attempts to establish causes

or risk factors for certain problems. This is done by comparing two or more groups, some of which have or develop the problem and some of which have not.

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Study Design

• Example of small-scale studies:– Two district health teams (DHT) that are functioning well and two

that do not function satisfactorily, in order to detect the possible reasons for bottlenecks in the functioning of the district health teams;

– One community with high and another with low participation in health activities, in order to identify factors that contribute to community participation;

– 20 mothers who delivered in a maternity and 20 who delivered at home, in order to identify possible reasons for the low percentage of supervised deliveries

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Study Design

Non-intervention

Exploratory

Descriptive

Comparative/ Analytical

Case-control

Cohort

Intervention

Experimental

Quasi-experimental

Comparative or analytical studies

Case-control• Study design that one group which has a

particular characteristic/disease (case) with another group without the characteristic/ disease (control) in order to find out what factors have contributed to that characteristic /disease

• Matched on certain variables but not on which one expects to cause the problem

• Usually use historical (retrospective) data

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Case-control

Risk factor present

Risk factor absent

Risk factor present

Risk factor absent

COMPARE

CASES

CONTROLS

PRESENTPAST(Retrospective study , looking backward)

Case-control

Derives:

•Odd ratios

•Cause-effect relationships

A measure of association.It is the ratio of the risk of disease in an exposed population to that in unexposed.

Odds ratio = (a/c) (b/d)

= ad/bc

Where,

Control Exposed Not Exposed Exposed a b

Case Not Exposed c d

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Advantages• Relatively cheap to conduct

• Relatively quick to carry out

• Able to show causal relationship

Disadvantages• Dependant on the availability

and quality of existing data

• There might be difficulty in matching the cases

• Selective survival might bias the comparison

• Unable to calculate incidence rates

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Case-control

Examples:

•Cancer Aetiological study

•Hepatitis B and Hepatoma study

•Study of the relation between sinusitis and subsequent risk of multiple sclerosis

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Case-control

• Study in which subjects, initially disease free, are followed up over a period of time. Some will be exposed to some risk factor, while some will not.

• A prospective study

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Cohort

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Cohort

Problem present

Problem not present

Problem present

Problem not present

COMPARE

Exposed to risk factor

Not exposed to risk factor

FUTUREPRESENT(Prospective study , looking forward)

(Source: Holland et all., 1985)

Derives:

•Relative risk

•Cause-effect relationships

It is the ratio of the incidence rates in an exposed population to that in unexposed.

Relative risk = Incidence among exposed Incidence among unexposed

= a/(a+b)

c/(c+d)

Where,

Disease Status Exposed Not ExposedRisk Exposed a bFactor NotStatus Exposed c d

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Cohort

Advantages• Able to show the

characteristic preceded the disease

• Can establish cause-effect relationships

• Able to disclose other diseases related to the same risk factor

Disadvantages• It is a costly study

• Not always feasible

• Lost of subjects during follow-up

• Require large sample size

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Cohort

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Examples:

•Smoking and Lung Cancer

•“Birth Cohorts” Study

•Longitudinal Study of Aging

Cohort

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Study Design

Non-intervention

Exploratory

Descriptive

Analytical / Comparative

Case-control

Cohort

Intervention

Experimental

Quasi-experimental

Study Design

Experimental• Research designs "gold standard“• Most “rigorous” of all research designs• Provide cause-effect inferences• Need:

– Randomization – Control and treatment group– Intervention

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Experimental

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Can obtain:

•Cause-effect relationships

•Evaluation of the intervention

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Experimental

Advantages• Useful in

clinical/laboratory research

• Able to test cause-effect relationships

• Do not require large sample size

Disadvantages• It is an expensive study

• Ethical issues

• Difficult to conduct in a community-based research

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Experimental

Experimental

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Examples:

•Clinical / Drug Trial

•A Mental Health Experimental Study

Quasi-experimental

• “Quasi” = ‘as if’ or ‘almost’• Either no randomization or control group

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Quasi-experimental design is a form of experimental research used extensively in the social sciences and psychology

Advantages• Able to test cause-

effect relationships

• Useful for evaluation of intervention in the community

Disadvantages• It is an expensive study

• Ethical issues

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Quasi-experimental

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Examples:To perform an educational experiment, a class might be arbitrarily divided by alphabetical selection or by seating arrangement.

The experiment proceeds in a very similar way to any other experiment

A variable being compared between different groups, or over a period of time.

Quasi-experimental

Other design

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•Systematic review

•Meta-analysis

Systematic review

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•A systematic review is a comprehensive survey of a topic that takes great care to find all relevant studies of the highest level of evidence, published and unpublished, assess each study, synthesize the findings from individual studies in an unbiased, explicit and reproducible way and present a balanced and impartial summary of the findings with due consideration of any flaws in the evidence.•In this way it can be used for the evaluation of either existing or new technologies and practices.

Systematic review

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Meta-analyses

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•Meta-analysis is a systematic, objective way to combine data from many studies, and arrive at a pooled estimate of treatment effectiveness and statistical significance. •Meta-analysis can also combine data from case/control and cohort studies. •The advantage to merging these data is that it increases sample size and allows for analyses that would not otherwise be possible. •They should not be confused with reviews of the literature or systematic reviews.

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Meta-analyses

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QUESTIONS???

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THANK YOU