Basics in Epidemiology & Biostatistics Waqar H Kazmi, Farida Habib Khan
Page numbers followed by f refer to figure and t refer to table
Alternate hypothesis, types of 60
Analytical observational studies 14
Antibody test 106
Bar charts 46
Basic statistical tests 110
Bias 89
control of selection 92
interviewer 91
misclassification 91
types of 89
Biostatistics 51
Blinding 24
Calculating odds ratio 87
Case control study 15
design 15
Categorical data 43
Causes of CRI 11
Central tendency, measures of 51
Chronic kidney disease 11t, 62, 95, 134, 144f
Citing book reference 159
Citing internet and electronic sources 161
Citing journal article 157
Closed ended questions 116
Cluster random sampling technique 37
Cluster sampling 32, 36
Cohort studies 17
Comorbidity index 11
Comparative studies 14
Conduct research 4t
Consecutive manner 37
Consecutive sampling 37
Consent form 25
Convenience sampling 37
Coronary artery disease 22f
Coronary heart disease 94
Cross-sectional studies 12
design of 13
Cumulative incidence rate 73
Data analysis 123, 143
plan 120
Data collection techniques, overview of 115
Data processing 122
Data types, classification of 42
Descriptive analysis 143
Descriptive observational studies 10
Diabetes 6
Different data collection techniques 115
Disease frequency, measures of 69
Disease prevalence, effect of 108
Dissertation reference 161
Dissertation writing 151
Dissertation, format of 151
Dyspepsia 45
End-stage renal disease 131
Epidemiological study designs, types of 8, 9
Estimation and hypothesis testing 57
Ethical review board 25
Experimental study design, sketch of 21
Fever 45
Focus group discussion 118
Formulate analysis plan 60
Gender distribution of respondents 47f
General ethical principles 164
Generating hypothesis, observational designs for 8
Graphs 45
types of 45
Headache 45
Histograms 47
Hypertension 6
Hypothesis 57, 134, 135, 153
alternative 59
test of 59
Incidence 72
density rate 74
rates, special types of 73
Information bias 91
Interpretation 66, 86, 88
Journal article, title of 158
Journal title 158
Judgmental sampling 38
Laboratory values 11
Line graphs 48
Literature search, resources of 5
Lottery sampling technique 32f
Mapping and scaling 119
Mean, median and mode, example of 51
Methodology 129
Morbidity rate 75
Mortality rate 76
Multivariate analysis 146t
Multivariate regression analysis 149
Myocardial infarction, relation of 93t
Nausea 45
Negative predictive value 107
Nephropathy 7
Nonparametric tests 112
Nonprobability sampling techniques 31, 37
Null hypothesis 59
Numerical data 43
Observation bias 91
Odds ratio 86
Open-ended questions 116
Operational definition 134
Optional components 154
Oral contraceptive and breast cancer 87
Oral contraceptive use 93t
Page numbers 159
Participation and withdrawal 172
Pie charts 46
Population 30
Positive predictive value 107-109
clinical trials 27
surveillance 26
Probability sampling techniques 31, 32
Processing and analysis of qualitative data 126
Projective techniques 118
Prospective cohort study 17, 18
Qualitative data 43
Qualitative research 1
Quantitative data 43, 122, 123
Quantitative research 3
Quasi-experimental studies 25
Questions, types of 116
Quota sampling 39
Recall bias 91
References 155
study 140
writing 157
Research questions and study types 27
Research subjects, rights of 173
Research topic, selection of 3
classification of 2
types of 1
Retrospective cohort study 19
Sample data 60
Sample of title page 155
Sample size 95
calculation 139
calculation result 100t
estimation 95
for single group mean 96
for single proportion 95
method 138
procedure 30
techniques 31, 32f
Scatter plots 49
Selection bias 90
Significance level, selection of 60
Simple linear regression 81, 82f
Simple random sampling 32
Snowball sampling 38
technique 39
Solving hypothesis testing problems 65
Sorting data 121
Special package for social sciences 83
Standard error of mean 54
State appropriate conclusion 66
Steps in
hypothesis testing 60
writing dissertation 151
Stratified random sampling 32, 35
technique 36f
Study designs 8
Study duration 139
Study objective 153
Study purpose 169
Synopsis writing 129
Systematic random sampling 32, 33, 34f, 35f
Systolic blood pressure 45
Table of content 152
Title 152
page 152
Tuberculosis 16
morbidity rate of 75
Variables, types of 41
Variation, measures of 52
Volume number 159
Vomiting 45
Chapter Notes

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Introduction to ResearchCHAPTER 1

Research is a systematic process of collection and analysis of data and later on its interpretation so as to find solutions to a problem or any event around us (Fig.1.1).
Basically research is of two types, i.e. empirical and theoretical (Flow chart 1.1 for the classification of research). Empirical approach is based upon observation and experience, while theoretical is based upon theory and abstraction. Both empirical and theoretical research complement with each other to develop an understanding of the phenomenon, predict future events and prevent harmful events for the general welfare of the population of interest.
Empirical research is further divided into qualitative and quantitative.
Qualitative Research
This type of research is context based. Here there is an inquiry with the goal to understand a social or human problem so build up a complex and holistic picture of the phenomena of interest. The researcher interprets the results of perspectives or information taken from subjects.
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Figure 1.1: Research as a systemic process
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Flow chart 1.1: Classification of research
In logic, we often refer to the two broad methods of reasoning as the deductive and inductive approaches.
Deductive reasoning works from the more general to the more specific approach. Sometimes this is informally called a “top down approach”. Inductive reasoning works the other way, moving from specific observations to the broader generalizations and theories, called “bottom up” approach. Qualitative research is the inductive form.
There are three types of qualitative research, i.e. case studies, ethnographic studies and phenomenological studies.
  1. Case study is a descriptive study of a single entity with respect to time and entity.
  2. Ethnographic study is a study of a cultural group in a natural setting. A cultural group could be group of people who share a common location or any common social experience, e.g. prisons in jail or cultural group of Muslims.
  3. Phenomenological study is a human experience of a small group of people over a long period of time.
Quantitative Research
In quantitative research reality is studied objectively by the researcher. Theory or hypothesis is tested by using numbers and analyzed by statistical methods. This type of research is based on deductive form of logic. Ultimately, the researcher develops generalization and contributes to theory.
Three different types of quantitative research are experimental, quasi-experimental and surveys.
  1. In experimental type of research, there is random assignment of subjects to experimental conditions. The results are compared with controls.
  2. Quasi-experimental studies are similar to experimental studies with the exception that there is nonrandomized assignment of subjects to experiments.
  3. Surveys are cross-sectional studies using questionnaires or interviews with an intent of estimating the characteristics of a larger population based on a smaller group from that population. Health science research mostly deals with quantitative type of research approach.
Research is a systemic process starting from selection of research topic and ends at reporting the research findings at local/international journals or scientific meeting. The Table 1.1 gives details about various steps and relevant purposes in conducting research.
Main Criteria for Selecting a Research Topic
There are seven criteria for selecting a research topic.
  1. Relevance: Here consider the prevalence of the problem in which you are interested. In other words, how big is the problem.
  2. Innovation: It is good to look into a new problem but it is not always possible to work or search for new problems as you may have limited resources. Thus, you can work on the old problem but with a different perspective.
  3. Feasibility: It means the availability of different resources that you may need to carry out the research project. It includes manpower, money, material, machinery, skills and time, etc.
    Table 1.1   Steps to conduct research
    • Selecting a research topic and formulating objective(s)
    • To assess what questions will the study address
    • What will it measure?
    • Undertaking literature review
    • To establish why the question is important?
    • What is already known about it?
    • What new will this study assess?
    • Selecting a study design
    • To ensure that the research design matches the objectives set
    • Selecting the subjects
    • To ensure generalizability and validity
    • Identifying study
    • To be clear in context to:
      • Predictor variables
      • Outcome variables
      • Confounding variables
    • Collection of data
    • To ensure collection of data aligned to the objective(s) in a reliable and nonbiased manner
    • Analyzing data
    • To present quantifiable result and assess validity
  4. Acceptability: It is important to consider whether your proposal will be supported by the local authorities or not. It also includes the acceptability of the procedure or the method that you are going to apply on the community as certain communities have certain social boundaries that may hamper in your research procedure.
  5. Cost-effectiveness: Consider whether the resources which you are spending are worthwhile, for example, in terms of decline in morbidity/mortality rates or length of stay in hospital.
  6. Ethical consideration: It includes informed consent, beneficence, nonmaleficence (do no harm), and confidentiality of information taken, etc.
  7. Applicability of possible results and recommendations: Is it likely that the recommendations from the study will be applied? This depends not only on the blessing of the authorities but also on the availability of resources for implementing the recommendations. 5The opinion of the relevant stakeholders (i.e. potential clients and of the responsible staff) will influence the implementation of recommendations as well.
Every criterion that is mentioned above is graded from 1 to 3, 1 being low, 2 means medium, while 3 stands for high (Table 1.2). Hence, the maximum score that is possible for any topic is 21. The topic for which there is highest score should be chosen.
Relevant scientific literature could be searched through internet, medical journals, conference literature, newspaper or documents of government or nongovernment organizations. Usually internet is used as the process is quick, reliable and freely accessible.
Through internet one can link with library catalogues, online databases, like MEDLINE and a number of biomedical journals.
Researchers should give adequate time in conducting literature search as this will help in writing a good quality of synopsis and dissertation.
Before using internet for literature search, the researcher should set the keywords for the topic of interest.
Suppose a researcher wants to work on the complication nephropathy, among diabetic patients who are hypertensive. The keywords are diabetes, hypertension and nephropathy.
Table 1.2   Scale for rating research topics
Low (1)
Low (2)
Low (3)
Ethical consideration
After opening the PubMed window by directly entering or, the first keyword (diabetes) in the search bar (for) is entered. Approximately 160000 research papers will be displayed which is not manageable (Fig.1.2).
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Figure 1.2: PubMed window after entering the first keyword—“diabetes”
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Figure 1.3: PubMed window after entering the second keyword —“hypertension”
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Figure 1.4: PubMed window after entering the third keyword—“nephropathy”
After entering the second keyword (hypertension), the number of articles have also narrowed down to 16057 but still it is a very large figure (Fig.1.3).
After entering the third keyword (nephropathy), the number of articles will narrow down to just 3010 which is manageable (Fig.1.4).
  1. Dawson B, Trapp RG (Eds). Reading the Medical Literature. Basic and Clinical Biostatistics, 3rd edn. Lange Medical Books; McGraw Hill;  Singapore:  2001. pp.317-9.
  1. Fathalla MF, Fathalla MMF (Eds). What research to do? WHO Regional Publication, Eastern Mediterranean Series: A Practical Guide for Health Researchers. World Health Organization;  Cairo:  2004. pp.25-42.
  1. Harvard L. How to conduct an effective and valid literature search? [Online]. 2007 [cited 2008 Jul]; Available from: URL:
  1. Hulley SB, Newman TB. Getting started: the anatomy and physiology of clinical research. In: Hulley SB, Cummings SR, Browner WS (Eds). Designing clinical research. Lippincott Williams and Wilkins;  Philadelphia, PA:  2007. pp.3-15.
  1. Research and Scientific Methods. In: World Health Organization. Health research methodology: a guide for training in research methods. World Health Organization;  Manila:  2001. pp.1-10.