This document provides an introduction to research concepts and epidemiological studies. It defines key terms like research and health systems. It describes the three main categories of epidemiological studies as descriptive, observational, and experimental. Descriptive studies include cross-sectional studies and aim to describe occurrences. Observational studies like case-control and cohort studies analyze relationships between health status and variables. Experimental studies deliberately manipulate variables and measure outcomes through randomized controlled trials and other designs. The document outlines characteristics, importance, and challenges of research as well as principles of research methodology.

1. CMT06103: Operation
Research
Session 1: Introduction to Research
Jacob (R. Health Laboratory scientist)
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2. Learning tasks
At the end of this session, students are expected to be able to:
 Explain terminologies commonly used in research (research,
epidemiological studies, and health systems)
 Describe principles and importance of research methodology
 Outline the characteristics of research
 Describe the three categories (types) of epidemiological studies
(descriptive, observational and experimental)
 List advantages of each category of epidemiological study
 Identifying other types of operational research
 Outline challenges in conducting epidemiological research
 Explain principles of conducting research
2

3. Activity: Brainstorming
What is Research?
What is Health system?
3

4. Definition
Research:
Is a systematic investigation into and study of
materials and sources in order to establish facts
and reach new conclusions.
OR
Is a careful and systematic process of inquiry to
find answers to problem of interest
4

5. Research is a scientific inquiry aimed at
learning new facts, testing ideas etc.
It is the systematic collection, analysis and
interpretation of data to generate new
knowledge and answer certain question or
resolve a problem
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6. Definition cont…
Health system:
A holistic system of health promotion, disease prevention
and control, curative services, rehabilitation, regulatory
and support systems put in place
It includes all public and private sectors, institutions
which directly influence and support the health of
people, embedded in the wider environmental-context
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7. DEFINITION
Research methods include all those
techniques/methods that are adopted for
conducting a research.
Research Methodology – is the way of
systematically solving the research problem. A
science of studying how research is conducted
scientifically
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8. Principles of Research Methodology
1. Ethical Consideration: Code of conducts especially
when dealing with human subjects. There a 4
fundamental principals of research ethics:
o Justice (be fair)
o Respect persons
o Beneficence (share benefits)
o Non mal-eficence (do not inflict harm)
2. Representative sampling: Research conclusion relies
on representative sample
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9. Characteristics of Research
The following are characteristics of research:
 It originates with a question or problem.
 It demands a clear statement of the problem.
 It requires clear articulation of a goal, clear objectives and a plan
 It builds on existing data (using both positive and negative findings)
 It follows a specific plan or procedures guided by specific problem,
question, or hypothesis.
 It requires collection and interpretation of data.
 It is cyclical (helical) in nature.
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10. Importance of Research
Research provides knowledge of the
causes of diseases.
Research contributes to developing cure
and preventing diseases
Helps promoting health for all.
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11. Activity: Buzzing
What Epidemiological studies?
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12. Definition of Epidemiological studies
Epidemiological study: is Study of the
distribution and determinants of health-related
states among specified populations and the
application of that study to the control of health
problems
Most of Epidemiological studies them form a
main part of operational research
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13. Categories of Epidemiological studies
Epidemiolog
ical studies
Observatio
nal studies
Descriptive
E.g. Cross-
sectional
studies
Analytical
studies
E.g. Case-
control,
cohort
Experimen
tal studies
E.g. Clinical trials, Field trials, Community
trials
13

14. Categories of Epidemiological studies (2)
 These studies complement each other and should not be
considered as water-tight compartments.
 Descriptive study is limited to a description of occurrence of a
disease in a population.
 An Analytical study goes further by analyzing relationship
between health status and other variables.
 Experimental or intervention studies involve an active attempt
to change a disease determinant or the progress of a disease,
and are similar in design to experiment in other sciences.
14

15. Descriptive studies (1)
 Is the first phase of an epidemiological investigation.
 Concerned with distribution of disease or health-related characteristics
in human populations and identifying the characteristics with which the
disease in question seems to be associated
 Useful in formulation of an a etiological hypothesis
 Involves the following procedures:
 Defining the population to be studied
 Defining the disease under study
 Describe the disease by:
 Time
 Place
 Person
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16. Descriptive studies (2)
Cross-Sectional Study:
Involves observation of some subset of a
population of items all at the same time.
It assesses group's health status and
exposure status simultaneously i.e. a
snapshot in which the health status and
exposure are studied at the same time
Takes place at a single point in time
16

17. Descriptive studies (3)
Advantages of Cross-Sectional Study:
Is a snapshot i.e. the researcher does not
have to wait for the health outcome to occur
or estimate what the level of exposure was
likely to have been years ago.
Useful for hypothesis formulation
Disadvantages of Cross-Sectional Study:
Cause can not be inferred, because only
current health and exposure are being
studied.
Can miss cases of short duration
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18. Analytical studies
These studies looks at the entire population to
test the hypothesis
Used to determine:
 Whether or not a statistical association exists
between a disease and a suspected factor;
 If one exists, the strength of the association.
There are two main categories of
observational study
 Case-control studies
 Cohort studies
18

19. Case-Control studies (1)
 This is a type of study design, used to identify factors that may contribute to a
disease by comparing subjects who have the condition (the cases) with patients who
do not have the condition but are otherwise similar (the controls).
 In case- control study:
 Both exposure and outcome (disease) have occurred before the start of the study
 Proceeds backwards from the effect to cause;
 It uses a control or comparison group to support or refute an inference/hypothesis
 Has 4 basic steps:
Selection of cases and controls
Matching cases and control
Measurement of exposure,
Analysis and interpretation
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20. Case-Control studies (2)
Measurement of Exposure:
 Odds ratio is commonly used to estimate risk of exposure in
case-control studies.
 E.g in a study to assess the association between smoking and
lung cancer:
 Odds Ratio (Cross product ratio) = ad/bc = (33*27) /55*2)=8.1
 The risk of having lung cancers in smokers is 8.1 times than non-
smokers
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Cases (with lung
ca. )
Control (without
lung ca. )
Smokers 33 (a) 55(b)
Non-smokers 2(c) 27(d)
Total 35(a+c) 82(b+d)

21. Case-Control studies (3)
Advantages of Case-control studies:
 Is useful in establishing the association between exposure and diseases
 Can be used to study rare health outcomes
 Relatively less expensive as compared to cohort studies.
Disadvantages of Case-control studies:
 Carries greater potential for bias.
 Does not allow for broader-based health assessments, because only one
type of disease is studied at a time
 Is potentially affected by confounding factors that must be well controlled.
 Do not give any indication of the absolute risk of the factor in question.
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22. Cohort studies (1)
 Cohort is a group of people sharing a common characteristic or
experience within a defined time period. E.g. People who are
exposed to a particular vaccine or drug
 In cohort study the study groups (with a known risk factor) is
compared to another groups (without risk factor) and observed
over a period of time to determine the occurrence of the problem to
establish incidence of the studied disease
 There are two types:
 Prospective: the groups are defined before the study is done
 Retrospective: the groups are determined after data has been collected
 Relative risk is used as the measurement of exposure in
Prospective cohort study while Odds ratio is used in Prospective:
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23. Cohort studies (2)
Measurement of Exposure:
 Relative risk: is the ratio between incidence of disease among exposed and incidence among non-
exposed.
 E.g in a study to assess the association between smoking and lung cancer:
 Relative risk =
𝐼𝑛𝑐𝑖𝑑𝑒𝑛𝑐𝑒 𝑎𝑚𝑜𝑛𝑔 𝑒𝑥𝑝𝑜𝑠𝑒𝑑
𝐼𝑛𝑐𝑖𝑑𝑒𝑛𝑐𝑒 𝑎𝑚𝑜𝑛𝑔 𝑛𝑜𝑡 𝑒𝑥𝑝𝑜𝑠𝑒𝑑
=
𝑎/(𝑎+𝑏)
𝑐/(𝑐+𝑑)
=
33/88
2/29
=5.4
 The risk of having lung cancers in smokers is 5.4 times than non-smokers
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Exposure
status
With lung No lung ca. Total
Smokers 33 (a) 55(b) 88(a+b)
Non-
smokers
2(c) 27(d) 29(c+d)
Total 35(a+c) 82(b+d)

24. Case-Control studies (3)
Advantages of Case-control studies:
 A desirable design because exposure precedes the health outcome, a
condition necessary for causation
 Less subject to bias because exposure is evaluated before the health
status is known.
Disadvantages of Case-control studies:
 The cohort study is also time consuming and the most logistically
difficult of all the studies.
 It is not suitable for rare conditions.
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25. Experimental studies (1)
 In experimental studies the investigator deliberately manipulates persons,
objects or situations and measures the outcome of the manipulations.
 It involves random assignment and techniques of blinding.
 Experimental studies are used in more detailed phase, in which experiments are
performed under more controlled conditions to test the hypotheses established
by descriptive studies and observational studies to confirm association or
efficacy.
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26. Experimental studies (2)
They are of two types:
 Clinical trials – randomised controlled trials
 Non randomised trial
 Clinical trial randomised but not controlled
 Community based interventions-randomised and controlled
 Community based interventions –non randomised but controlled
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27. Experimental studies (2)
 Randomized control-studies has 6 basic steps
 Drawing up a protocol
 Selecting reference and experimental populations
 Randomization
 Manipulation or intervention
 Follow-up 6
 Assessment of outcome
 Experimental studies are greatly limited by:
 Ethical and legal considerations
 Difficulties involved in securing the cooperation of a large number of people.
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28. Challenges in Conducting Epidemiological
Studies
Recall bias
Selection bias
Confounding
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29. Key points
Research Is a careful and systematic process of inquiry
to find answers to problem of interest
There are three main categories of research:
observational, analytical and experimental studies
The three categories of research compliments one
another
Conduction of research is prone to challenges including
Recall bias, Selection bias and Confounding
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30. Review questions
1. What is research?
2. Describe the categories of research
3. Describe principles of research
methodology?
30

31. References
Kothar, C.R. (2004). Research
Methodology: Methods and Techniques
(2nd ed.). India: New Age International (P)
Limited
https://www.slideshare.net/iq1086/types-
of-epidemiological-designs
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32. END
THANKS
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