overview on research methodologies

1. Overview of research design
Dr Tong Seng Fah
MBBS (UM) MMed (Fam Med) (UKM) PhD (Sydney) AM
Professor of Family Medicine
Department of Family Medicine UKM

2. Choosing an appropriate methodology
methods
Research
question
Answer
Methods are the vehicle you
choose to reach the destination

3. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology

4. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology
Focus on how MUCH, what when,
(the magnitude of the problem)
Focus on
What,
How, why

5. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology

6. 1. Qualitative
Example:
What people say about taking vitamin?
Why people take vitamin?
Why patient refuse insulin?
How patient makes decision on going for health
screening?
What are the experiences of being diagnosed to
have cancer?

7. 1. Qualitative
• Types of questions
asked:
– What
– Who
– Why
– How
• Focus on:
– Looking out for concepts
• Methods:
– Observe
– Interviews
– Focus group discussion
– Participate in the
researched community
– Going through
documents, artifacts
– Take photos
– Audio tapping
– Video tapping

8. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology

9. 2. Cross sectional study
“Snap” shot on a specific time
Depression
Erectile dysfunction
ED is associated with depression; also
depression is associated with ED
blinded blinded

10. 2. Cross sectional study
“Snap” shot on a specific time
Hence
Unable to infer causal relationship
Depression
Erectile dysfunction
Known natural history through cohort study

11. 2. Cross sectional study
• Types of questions asked:
– What is the magnitude?
– How large / small?
(Prevalence, proportion)
– Association between
factors
– The strength of the
association
• Focus on
– description of a particular
phenomena of interest
– On a particular population

12. 2. Cross sectional study
• Types of questions asked:
– What is the magnitude?
– How large / small?
(Prevalence, proportion)
– Association between
factors
– The strength of the
association
• Focus on
– description of a particular
phenomena of interest
– On a particular population
• Methods:
– Determine the variables of
interest (ED, Depression)
– Probabilistic selection of a
representative sample
– Selection of measurement
tools (with questionnaire)
– Analysis:
• Descriptive statistics
• Inferential statistics: is
there a difference
• OR, regression analysis

13. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
For the specific
participants
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology

14. 3. Case-control
• Study looks backwards from effect to possible
cause
http://hihg.med.miami.edu/code/http/modules/education/Design/Print.asp?CourseNum=4&LessonNum=4
Good for rare disease, new disease

15. 3. Case-control
• Example:
Odds of getting cancer among smokers: 20:4
Odds of getting cancer among non-smokers: 5:21
Odds ratio of smokers getting cancer: (20:4): (5:21)
(20/4)/(5/21)= 21 times the odds
Smoking
Lung cancer (n=50)
Yes No
Yes 20 4
No 5 21

16. 4. Cohort
• Prospective follow up of a group of
participants before occurrence of study
outcome (disease, death, complications)
Cardiovascular risk factors
Known natural history through cohort study
Start
No cardiovascular risk factors Developing
CV
events?

17. 4. Cohort
Case- control Cohort

18. 4. Cohort
Case- control Cohort

19. 4. Cohort
• Example:
Incidence of cancer among smokers: 10/500= 2.00%
Incidence of cancer among non-smokers: 5/900=0.556%
Relative risk of smokers getting cancer:
2.00% ÷ 0.556% = 3.6
Smoking
Lung cancer
Yes No
Yes (n=500) 10 490
No (n=900) 5 895

20. Comparing the 3 observational
quantitative studies
• It is a matter of time
Cardiovascular risk factors
Cohort:
start with
exposure
No cardiovascular risk factors
Snap-shot: study the present
disease and exposure
Case control:
start with cases
and look back at
the exposure
Problems
with
confounding
factors
(do you
know why)

21. Comparing the 3 observational
quantitative studies
Problems
with
confounding
factors
(do you
know why)
Male Myocardial
infarct

22. Comparing the 3 observational
quantitative studies
Problems
with
confounding
factors
(do you
know why)
Male
smoking
Myocardial
infarct

23. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology

24. 5. Diagnostic study
• Comparing the test and gold standard
Test
Gold standard
Positive Negative
Positive 80 10 +ve predictive
value = 80/90
Negative 2 88 -ve predictive
value =88/90
Sensitivity =
80/82
Specificity =
88/98

25. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology

26. Randomised controlled trial
• Experimental trial that involves intervention group
versus controlled group
• All confounding factors (either known or unknown)
are assumed to be equal between two groups
because of randomisation.

27. Randomised controlled trial
http://library.downstate.edu/EBM2/2200.htm

28. Exploratory
Aetiological
Diagnostic
Treatment effect
Prediction
Qualitative
Quantitative
Cross sectional
Case-control
Cohort
Randomised
control trial
Choosing an appropriate methodology

29. Choosing an appropriate methodology
• Other factors to be considered:
1. Cost
2. Time
3. Manpower
4. Ethical issues
5. Your expertise

30. Thank you