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 a number of approaches, e.g. may use both quantitative and qualitative 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 Two factors characterized a study design: Time Intervention

Time Perspectives Cross-sectional Retrospective Prospective 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

Study Design Categories Non-intervention Exploratory Descriptive Analytical / Comparative Case-control Cohort Intervention Experimental Quasi-experimental

Types of Study Design Descriptive Case-Control Cohort Experimental Quasi-experimental

Analytical / Comparative Study Design Study Design Non-intervention Exploratory Descriptive Analytical / Comparative Case-control Cohort Intervention Experimental Quasi-experimental

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.

Study Design Descriptive studies involves describing the characteristics of a particular situation, event or case. to answer WHAT , WHERE, WHEN and HOW

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.

Descriptive Derives: Prevalence rates Association between variables

Descriptive Advantages Disadvantages Relatively cheap to conduct Relatively quick to carry out Captures the situation at only one point in time Unable to show causal relationship

DIRECT CAUSAL RELATIONSHIP INDIRECT CAUSAL RELATIONSHIP COMPLEX CAUSAL MODEL INCOME LEVEL SEX INCOME LEVEL SEX EDUCATION LEVEL OCCUPATION EDUCATION LEVEL OCCUPATION INCOME LEVEL SEX FAMILY RESPONSBILITY PART TIME WORK

Descriptive 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

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.

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

Comparative or analytical studies Study Design Non-intervention Exploratory Descriptive Comparative/ Analytical Case-control Cohort Intervention Experimental Quasi-experimental

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

Case-control PAST PRESENT (Retrospective study , looking backward) Risk factor present CASES Risk factor absent COMPARE Risk factor present CONTROLS Risk factor absent

Case-control Derives: Odd ratios Cause-effect relationships Case Not 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 Derives: Odd ratios Cause-effect relationships

Case-control Advantages Disadvantages Relatively cheap to conduct Relatively quick to carry out Able to show causal relationship 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

Case-control Examples: Cancer Aetiological study Hepatitis B and Hepatoma study Study of the relation between sinusitis and subsequent risk of multiple sclerosis

Cohort 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

Not exposed to risk factor Cohort PRESENT FUTURE (Prospective study , looking forward) Problem present Exposed to risk factor Problem not present COMPARE Problem present Not exposed to risk factor Problem not present (Source: Holland et all., 1985)

Cohort 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 Exposed Risk Exposed a b Factor Not Status Exposed c d Derives: Relative risk Cause-effect relationships

Cohort Advantages Disadvantages Able to show the characteristic preceded the disease Can establish cause-effect relationships Able to disclose other diseases related to the same risk factor It is a costly study Not always feasible Lost of subjects during follow-up Require large sample size

Cohort Examples: Smoking and Lung Cancer “Birth Cohorts” Study Longitudinal Study of Aging

Analytical / Comparative Study Design Study Design Non-intervention Exploratory Descriptive Analytical / Comparative Case-control Cohort Intervention Experimental Quasi-experimental

Experimental Research designs "gold standard“ Most “rigorous” of all research designs Provide cause-effect inferences Need: Randomization Control and treatment group Intervention

Experimental

Experimental Can obtain: Cause-effect relationships Evaluation of the intervention

Experimental Advantages Disadvantages Useful in clinical/laboratory research Able to test cause-effect relationships Do not require large sample size It is an expensive study Ethical issues Difficult to conduct in a community-based research

Experimental Examples: Clinical / Drug Trial A Mental Health Experimental Study

Quasi-experimental “Quasi” = ‘as if’ or ‘almost’ Quasi-experimental design is a form of experimental research used extensively in the social sciences and psychology “Quasi” = ‘as if’ or ‘almost’ Either no randomization or control group

Quasi-experimental Advantages Disadvantages Able to test cause-effect relationships Useful for evaluation of intervention in the community It is an expensive study Ethical issues

Quasi-experimental 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.

Other design Systematic review Meta-analysis

Systematic review 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

Meta-analyses 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.

Meta-analyses

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