1. Research Methodology: An Overview
Ahmed Mandil,
Prof of Epidemiology
King Saud University, Riyadh, KSA

2. Headlines Health research Choice of subjects Data collection methods
Sources of data
Study designs (qualitative, quantitative)
Choice of study design
Health research proposal
Literature review
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Research Methodology

3. Health Research
Lab research: applies knowledge of basic sciences towards development of procedures and strategies to prevent, control and understand mechanisms of health-related phenomena
Population-based (field) research: study of distribution, determinants, control measures of health-related phenomena in chosen populations, followed by application of suitable biostatistical techniques which may allow generalization of results
Healthcare-facility (clinical) research: application of epidemiological principles in research based in healthcare facilities, e.g. randomized clinical trials
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Research Methodology

4. Research Characteristics
Has a clearly stated question(s) and hypotheses (null, alternative)
Has a specific plan of action
Builds on existent knowledge
Generates NEW data, which answers the original question(s)
Opens horizons for further enquiries and research
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Research Methodology

5. Subjects & Data Collection
Selected Units: individuals, groups
Study Populations: cross-sectional, longitudinal
Data collection timing: prospectively, retrospectively, combination
Data collection types: primary, secondary
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Research Methodology

6. Study Populations
Cross-sectional: where ONLY ONE set of observations is collected for every unit in the study at a certain point in time, disregarding the length of time of study as a whole (health surveys’ populations are of this type)
Longitudinal: where TWO-OR-MORE sets of observations are collected for every unit in the study, i.e. follow up is involved in order to allow monitoring of a certain population (cohort) over a specified period of time.
Dynamic: gains and loses members
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Research Methodology

7. Data Collection Types
Primary: where the investigator is the first to collect the data. Sources include: medical examinations, interviews, observations, etc. Merits: less measurement error, suits objectives of the study better. Disadvantage: costly, may not be feasible.
Secondary: where the data is collected by OTHERS, for other purposes that those of the current study. Sources include: individual records (medical / employment); group records (census data, vital statistics)
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Research Methodology

8. Data Collection Sources
Routine systems (e.g. vital statistics: births / deaths; health insurance; communicable diseases)
Surveys (interviews; telephone; mail; self-administered)
Disease registries (hospital / community – based)
Sentinel event recording systems (health; disease; health services)
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Research Methodology

9. Study Design: Definition
A study design is a specific plan or protocol for conducting the study, which allows the investigator to translate the conceptual hypothesis into an operational one.
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Research Methodology

10. Study Designs: Types Qualitative Quantitative Experimental
Observational
Basic
Hybrid
Incomplete
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Research Methodology

11. Types of quantitative designs
Observational designs: studies that do not involve any intervention or experiment.
Experimental designs: studies that entail manipulation of the study factor (exposure) and randomization of subjects to treatment (exposure) groups
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Research Methodology

12. Observational Designs
Exploratory: used when the state of knowledge about the phenomenon is poor: small scale; of limited duration.
Descriptive: used to formulate a certain hypothesis: small / large scale. Examples: case-studies; cross-sectional studies
Analytical: used to test hypotheses: small / large scale. Examples: case-control, cross-sectional, cohort.
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Research Methodology

13. Cross-sectional Studies (Community health studies, surveys)
Characteristics: detects point prevalence; relatively common conditions; allows for stratification; different from surveillance / registers
Merits: feasible; quick; economic; allows study of several diseases / exposures; useful for estimation of the population burden, health planning and priority setting of health problems
Limitations: temporal ambiguity (cannot determine whether the exposure preceded outcome); possible measurement error; not suitable for rare conditions; liable to survivor bias
Effect measure: Odds Ratio + CI
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Research Methodology

14. Case - Control Studies
Characteristics: two source populations; assumption that non-cases are representative of the source population of cases.
Merits: least expensive; least time-consuming; suitable for study of rare diseases (especially NCDs)
Limitations: not suitable for rare exposures; liable to selection bias and recall bias; not suitable for calculation of frequency measures.
Effect measure: Odds Ratio + CI
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Research Methodology

15. Cohort Studies
Characteristics: follow-up period (prospective; retrospective)
Merits: no temporal ambiguity; several outcomes could be studied at the same time; suitable for incidence estimation
Limitations (of prospective type): expensive; time-consuming; inefficient for rare diseases; may not be feasible
Effect measure: Relative Risk + CI
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Research Methodology

16. Cohort Design disease Factor present no disease Study population
free of
disease
disease
Factor
absent
no disease
Cohort Design
present
future
time
Study begins here
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Research Methodology

17. Experimental Designs
Types: Lab experiments; Randomized Clinical trials; Community interventions studies. These types are differentiated by: number of participants and duration
Merits: control of confounders
Limitations: limited generalizability; possibility of unethical randomization; impracticability under some settings
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Research Methodology

18. Experimental Design time outcome Intervention no outcome Study
RANDOMIZATION
Intervention
no outcome
Study
population
outcome
Control
no outcome
Experimental Design
baseline
future
time
Study begins here (baseline point)
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Research Methodology

19. Choice of Study Design (I)
Depends on:
Research Questions
Research Goals
Researcher Beliefs and Values
Researcher Skills
Time and Funds
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Research Methodology

20. Choice of Study Design (II)
Status of existent knowledge
Occurrence of disease
Duration of latent period
Nature and availability of information
Available resources
Time constraints
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Research Methodology

21. Health Research Proposal Components
Executive Summary
Literature review & rationale
Objectives & hypothesis
Methodology
Ethical considerations
Chronogram
Budget
References
Investigating team
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Research Methodology

22. What is a good proposal ? Credible innovative research question
Meticulously designed research plan
Carefully selected research team
Attractively presenting all of the above, so that it:
Communicates clearly & concisely
Follows a logical outline
Indicates merits and limitations of the plan, but
Makes sure that merits do stand out (for a busy reviewer)
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Research Methodology

23. Literature Review Peer consultation
Databases (search engines: e.g. Pubmed; Medline; Ovid; IMEMR at WHO / EMRO website)
Published literature (scientific journals)
Published literature (electronic journals)
Grey literature (theses: masters / doctoral; reports: ministry of health / social affairs / annual statistics; national census, others)
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Research Methodology

24. References
Porta M. A dictionary of epidemiology. 5th edition. Oxford, New York: Oxford University Press, 2008.
Fathallah MF, Fathallah MMF. A practical guide for health researchers. Cairo: WHO, 2004.
Rothman KF, Greenland S, Lash TL. Modern Epidemiology. 3rd edition. Philadelphia: Walter Kluwer, Williams & Wilkins 2008:
Gordis L. Epidemiology. 4th edition. Philadelphia, Pennsylvania: Elsevier Science, 2008 
Beaglehole R, Bonita R, Kjellstrom T. Basic epidemiolgy. 2nd edition. Geneva: World Health Organization, 2006
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Research Methodology

25. Thank you for your kind attention
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Research Methodology