Introduction to Research methodology

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Introduction to
Research Methodology
For Basic Research Workshop
Prof. Dr. Jamalludin Ab Rahman B.Med.Sc., MD, MPH
Departm...

The programme
Day 1
 Getting the research idea
 Literature review & managing them (using EndNote)
 Building conceptual ...

The programme….
Day 2
 Plan for statistical analysis – preparing dummy table
 Basic statistical analysis
 Descriptive s...

Contents
 Why we do research?
 How we do research?
 Effective literature search & management
 Choosing best study desi...

Why we do research?
 Answers our curiosity?
 Forced by our superior
 For promotion
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Start with end in mind
(Bijaksana)
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Idea
Justify Explore Strategize
Collect
Analyse Report Publish
Initiation
Planning &
strate...

The 4 Critical Strategies
1. Clear conceptual framework
2. SMART objectives
3. Detail data dictionary
4. Expected dummy ta...

Organise your research idea
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Identify variables involved
 Main outcomes (dependant)
 Explanatory (exposures, factors)
variables (independent)
 Confo...

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Exposure Outcome
Confounder

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Alcohol-
based
mouth wash
Oral Cancer
Smoking

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Varkevisser, C. M.,
Pathmanathan, I.,
& Brownlee, A. T.
(2003). Designing
and co...

Figure 3 Structural Equation Model Showing the Relationship Between
Family Processes, Child Characteristics, and Achieveme...

Thornley S (2012)
Causation and
Statistical Prediction:
Perfect Strangers or
Bedfellows?
J Biom Biostat 3:e115.
doi:10.417...

Literature Review and
Bibliographic Management
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Research add
more information
to the circle of
knowledge

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Research
Information
New
knowledge
Literature

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Literature review is not
 A chronological catalogue of all
material,
 A collection of quotes or
paraphrases, or
 A sale...

Literature review is
 Organised
 Structured
 Evaluated (critically appraised)
research materials
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The steps – 5S
1. Strategise (plan) Most important step
 Get your topic, problem statement & conceptual framework
ready ...

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Strategise
Search
Sort
Summarise
• Based on problem
statement &
conceptual
frame...

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Strategise
Search
Sort
Summarise
• What is OSA?
Diagnosis
• Prevalence of OSA
• ...

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The number of articles found
Alternative spelling
How they were sorted
Time peri...

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Domains of interest. Can assign
many domains for one article
Customise the heade...

Phrasing objectives
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SMART
 Specific – What you really want to do
 Measurable – Must be able to be measured
 Attainable – Achievable
 Relev...

e.g.
 To determine the prevalence of breastfeeding among
mothers
Can rephrase to:
 To measure the prevalence of exclusiv...

Choosing Best
Research Designs
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Research design
Design
Observational
Cross
sectional
Case-control
Cohort
Experimental
Animal Trial
Clinical Trial
Communit...

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Cause & Effect
EffectCause
Cause precedes effect
Time
Exposure Outcome
Smoking L...

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Cross sectional study
EffectCause
Exposure Outcome
Smoking Lung cancer
High fat ...

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Case-Control study
EffectCause
Exposure Outcome
Smoking Lung cancer
High fat die...

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Cohort study
EffectCause
Exposure Outcome
Smoking Lung cancer
High fat diet Obes...

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Experimental study
Effect
Cause
(New
drug)
Effect
Other
cause
(Control)

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Experimental study
Effect
New
drug
Effect
Control
No effect
No effect
Randomisat...

Hierarchy of
Evidence
Randomised
controlled trial
Cohort
Case control
Case report
Expert opinion
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Cross sectional study
 Population based – represent population
 Measure exposure & outcomes at the same point in time –
...

Cross sectional study
Advantages
 Measure prevalence of a
population
 Measure multiple exposures &
outcomes
 Relatively...

Cross sectional study - Example
 NHMS ~ Household study, all Malaysian (N=47,610 for
2006)
 NOHSA ~ Adult (>15) (N=14,44...

Case control study
 Fix the outcomes, measure the exposures
 Longitudinal
 Retrospective
 Case = outcome of interest
...

Case control study
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Research methodology for nurses 48
Case
Control
No exposure
Exposure
No exposure
Exposure
Hi...

Lung Cancer
No Lung
Cancer
Smoking 20 (18.2%) 90 (81.8%)
Not Smoking 5 (4.5%) 105 (95.5%)
2 (df=1)= 10.150, p =0.001, OR ...

Cases
 Well defined
 Source – institution
vs. population
Control
 Matched vs. Unmatched
 Matching ~ controls
resemble ...

Case control study
Advantages
 Good for rare conditions or
diseases
 Less time needed to conduct the
study because the c...

Example
 Tobacco use and risk of
myocardial infarction in
52 countries in the
INTERHEART study: a
case-control study. (Te...

Cohort study
 Measure outcomes
 Compare incidence of a disease (or condition) among
exposed and unexposed individuals ov...

Cohort study
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Disease
No disease
No exposure
Exposure
Now Future
Lung cancer
No l...

Define cohort
 Both exposed & not exposed groups have equal chance
to:
 Develop disease
 Be followed-up
 Types:
 Repr...

Measurements
 Exposure
 Carefully defined in advance
 Standard measurement for both E+ & E- groups
 Outcome
 Primary ...

Follow-up
 Keep participation at > 90%
 Equal likelihood to detect disease in all subjects
 Active vs. Passive follow-u...

Example Obesity as an Independent Risk Factor for
Cardiovascular Disease: A 26-year Follow-up of
Participants in the Frami...

Cohort study
Advantages
 Infer causality
 Measure multiple outcomes
 Study rare exposure
 Measure incidence
Disadvanta...

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Sampling Plan
(Sampling technique & sample size)
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Before we sample
Determine study place, duration & subjects
 Describe study place
- especially if plan to represent a pop...

Subjects
 Target population
 Study population
 Sampling frame
 Sampling unit
 Observation unit
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Example – NHMS III 2006
 Target population
 Study population
 Sampling frame
 Sampling unit
 Observation unit
9April2...

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Random Non-Random
Represent a population
Must have sampling frame
• Simple
• Sys...

Simple
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Systematic
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1 2 43
A
B
C
D
E

Cluster
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Stratified
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Random sampling
Random
Simple
Systematic
Stratified
Cluster
Multistage
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The ideal...

Non random sampling
Non random
Convenience
Purposive
Quota
Snowball
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Haphazard. G...

Example – NHMS III 2006
Two stage stratified random sampling
 Target population
 Study population
 Strata
 Clusters
 ...

Example – A clinical trial
 Target population All diabetic patients
 Study population Diabetic for at least 1 year on
in...

Why we calculate sample size?
 Estimate sample required for external validity (inference)
& logistic preparation
 Justif...

Sample size is an estimate
 Best sample size for specific purpose (for the main
objective)
 Never an exact value, always...

Plan with the end in mind
 No one formula fits all
 Depending on objective:
1. Represent population
2. Hypothesis testin...

Pre-requisites
 Objective determined
 Sampling method known
 Estimate the outcome
 Precision required
 Statistical te...

Represent population
 Represent population e.g. state, district, village,
institution etc
 Usually for prevalence study ...

Single proportion
 𝑛 =
𝑧 𝛼/2
2 𝑝(1−𝑝)
𝑑2
 Where z = value from standard normal distribution
corresponding to desired con...

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95% CI is a = 0.05
a/2 = 0.025
𝑧 𝛼/2 =1.96
Power 80% or 0.8
1-b = 1-0.8 = 0.2
b ...

Example
 Study to measure prevalence of hypertension in a village
of 1000 people
 Expected prevalence = 40%, Precision =...

Single mean
 Study to measure one sample mean
 𝑛 = (
𝑧 𝛼/2∗𝑠
𝑑
)2, where s = expected standard deviation
(SD)
 We use s...

Example
 Study to measure average DMF among adults in a
village of 2000 people
 Estimated DMF = 11 (SD 10) with the prec...

Hypothesis testing
 How one variable is different from the other
 E.g. different % of hypertension between male & female...

Compare two proportions
 𝑛 =
(𝑧 𝛼
2
+𝑧 𝛽)2∗(𝑝1 1−𝑝1 +𝑝2 1−𝑝2 )
(𝑝1−𝑝2)2
 Total sample size = 2*n
 Where p1 and p2 are t...

Example
 A study to compare prevalence of diabetes mellitus
between male and female. Expected prevalence are
30% vs. 40% ...

Compare two means
 𝑛 =
2∗ 𝑧 𝛼
2
+𝑧 𝛽
2∗𝑠2
𝑑2
 Where d=smallest means difference and s = standard
deviation
 Total sampl...

Example
 A study to compare means of HbA1c between diabetic
treated with new drug versus the standard drug (control).
Exp...

Using applications
 Software or online calculators
 Make sure the formula is valid
 Suggestion:
 PS: Power and Sample ...

Epi Info – Population survey
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Epi Info – Cohort & Cross-sectional
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Open Epi –
Compare two
means
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PS - Dichotomous
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PS – Compare
two means
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Planning for Data Collection
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You wanna collect now?
1. Objectives are clear
2. Variables identified & defined
3. Samples identified
4. Instrument valid...

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Variables identified & defined
Conceptual
framework
Identify variables
Define va...

How to define variable?
 Definition
 Working/operational definition
 How it will be measured
 Precision of measurement...

Furnish the info for each variable
e.g. Obesity
 Definition
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Overweight and obe...

Furnish the info for each variable
e.g. Obesity
 Definition
 Working definition
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Furnish the info for each variable
e.g. Obesity
 Definition
 Working definition
 How it will be measured
 Precision of...

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Make sure the instrument are valid & reliable

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NATIONAL HEALTH AND
NUTRITION EXAMINATION
SURVEY III. Body
Measurements
(Anthro...

Furnish the info for each variable
e.g. Obesity
 Definition
 Working definition
 How it will be measured
 Precision of...

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Then only you start to design
the data collection form

Tools to create form
 Usual word processing (e.g. Word), spreadsheet (e.g.
Excel)
 Better with Database (Microsoft Acces...

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• Test the form
• Do complete testing
• Revise the form
• Run some analyses

Plan for Statistical Analysis
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Research idea
General objectives
Specific Objective Specific Objective Specific...

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Type of statistical analysis
AnalyticalDescriptive
e.g. Describe socio-
demogra...

Steps for the plan
1. Focus on each specific objective
2. Decide whether it will be descriptive or analytical
3. For descr...

Dummy table - example
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Data quality
 Valid value
e.g. age > 200 years, weight > 500 kg, pregnant male
etc
 No missing value
 Relevant skip res...

How to report the results
 Start with descriptive statistics – usually for baseline
findings e.g. description of study po...

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Type of data
(Level of measurement)
Categorical
Nominal Ordinal
Numerical
Discr...

Data
Categorical
Frequency
(count) &
Percentage
Numerical
Normal Mean (SD)
Not Normal
Median
(Range/IQR)
How to describe a...

Bivariable analysis
 Compare numericals – compare means, compare ranks,
correlation
 Compare proportions – chi-square
9A...

Bivariable analysis
Dependent variable
(outcome)
Numerical Categorical
Independent
variable
(factor)
Numerical Correlation...

Bivariable analysis - detail
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Variable 1 Variable 2 Test
Categorical Categorical...

Multivariate test
Dependant Independent variables Test
Numerical All numerical Linear regression
Numerical Numerical & cat...

Specific test
 Survival analysis – time to event analysis
 Time series – observe trend over time & forecasting
 Factor ...

How to publish your research
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Howtowritea
researchpaper
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Title
Method
Discussion
& conclusion
State
objectives
Results
I...

Before you write
 Decide the target audience
 Scientific publication or report
 Choose journal
 Study the format & req...

The structure
Publication
 Title
 Abstract
 Keywords
 Introduction
 Method
 Results
 Discussion
 References
Report...

The suggested sequence
1. Based on specific objective, analyse the data & produce
planned tables
2. Interpret & describe t...

Writing result
 Describe your result (no discussion)
 No reference (usually)
 Text vs. table vs. graphic (no redundancy...

Writing discussion
 Should answer the research questions mentioned in
Introduction
 Discuss the result
 Do not repeat t...

Research Management
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Other things to plan
1. Ethical consideration – consent form, advisory
committee
2. Budget
3. Approval
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In summary, what are the critical
information
1. Specific objectives
2. Conceptual framework
3. Data dictionary
4. Dummy t...

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