RESEARCH METHODOLOGY public health dentistry

Studies

1. METHODOLOGY
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

2. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

3. In science credit goes to the man
who convinces the world,
not the man to whom the idea first occurs.
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

4. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

5. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
“Researchisaquestfor
knowledgethroughdiligent
searchorinvestigationor
experimentationaimedatthe
discoveryandinterpretationof
newknowledge.”

6. 6
TYPES OF RESEARCH
1. BASIC Vs APPLIED
5. PRIMARY Vs SECONDARY
4. CONCEPTUAL Vs EMPIRICAL
3. QUALITATIVE Vs QUANTITATIVE
2. OBSERVATIONAL Vs EXPERIMENTAL
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

7. 7
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
NOMINAL ORDINAL
INTERVAL RATIO
DISCRETE
Theyarecalledasattributes.
Theyarequalitativeinnature
e.g.Race,Sex,Religion…..
CONTINUOUS
Theyarealsocalledvariables.
Theyarequantitativeinnature.
e.g.Height,weight,RBC’count..
TYPES OF DATA

8. HIERACHY OF EVIDENCE
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

9. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

10. 10
Directional hypothesis
Non directional hypothesis
Research hypothesis
Null hypothesis
Simple hypothesis
Complex hypothesis
1
3
2
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
TYPES OF HYPOTHESIS
Increase in independent variable, will increase
the dependent variable
It will tell the association but not the direction
No dose-response relation
IQ increases and short time memory decreases as the age
increases.
IQ increases as the age increases.

11. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
P -Value

12. Confidence level 95% means…..
Significance level 5% means…..
SIGNIFICANCE LEVEL INDICATES THE LIKELIHOOD THAT THE ANSWER WILL FALL
OUTSIDE THAT RANGE.
CONFIDENCE LEVEL INDICATES THE LIKELIHOOD THAT THE ANSWER WILL FALL WITHIN
THAT RANGE.
If p <0.05, the
probability of getting a
difference between
groups purely by
chance or luck is less
than 5%

13. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

14. Finding Mean, Median and Mode in a given Data
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
Measures of Central Tendency:

15. SD -1 SD +1
SD -2 SD +2
SD -3 SD +3
9.30 am
9.20 am 9.40 am
Standard Deviation

16. Correctdecision Type 2 error
Probability = beta error
Type 1 error
Probability = Alfa
Correct decision
Sensitivity= correctly identify those who have the diseases
Specificity= correctly identify those who do not have the diseases
Universe of outcomes
True Positive
False Negative
False Positive
True Negative
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

17. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

18. PROBABILITY SAMPLING
Simple random sampling
Stratified random sampling
Cluster sampling
Multistage sampling
Systematic sampling
Pathfinder surveys
NON PROBABILITY SAMPLING
Convenience sampling
Consecutive sampling
Quota sampling
Judgment/Purposive sampling
Snow ball sampling
SAMPLING
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

19. 19
Classification
Experimental studies / Intervention studies
1. Randomized controlled trials
2. Field trials
3. Community trials
Observational studies
1) Descriptive studies
2) Analytical studies
Case-control study
Cohort study
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
STUDY DESIGNS

20. Descriptive Study
design
Is there any association Strength of AssociationConcrete Proof
Experimental designs
Cohort
study
Choose the study design based on the data you have…
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

21. DESCRIPTIVE STUDY DESIGN
STEPS
1) Defining the Populationto be studied
2) Defining the Diseaseunder study
3) Describing the disease by Time, Place, Person.
4) Measurementof disease
5)Comparingwith Known Indices
6) Formulation of an Etiological Hypothesis
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

22. ANALYTICAL EPIDEMIOLOGY
CASE-CONTROL STUDY STEPS
1) SELECTION OF CASES & CONTROLS
4) ANALYSIS & INTERPRETATION
3) MEASUREMENT OF EXPOSURE
2) MATCHING
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
COHORT STUDY STEPS
•Selection of study subjects
•Obtaining data on exposure
•Selection of comparison groups
•Follow up
•Analysis

23. POPULATION
CASES
PEOPLE WITH DISEASES
CONTROLS
WITH NO DISEASES
Exposed (a)
Not exposed (c)
Exposed (b)
Not exposed (d)
TIME
DIRECTION OF ENQUIRY
1) CASE-CONTROL STUDIES
ANALYTICAL EPIDEMIOLOGY

24. POPULATION
PEOPLE WITHOUT DISEASES
EXPOSED
NOT EXPOSED
DISEASES
NO DISEASES
DISEASES
NO DISEASES
DESIGN OF COHORT STUDIES
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
TIME
DIRECTION OF ENQUIRY

25. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
EXPERIMENTAL STUDY DESIGN
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
ANIMAL EXPERIMENT
HUMAN EXPERIMENT

26. THEY ARE BROADLY DIVIDED INTO TWO TYPES
1.RANDOMIZED CONTROLLED TRIALS:
2.NON RANDOMIZED TRIALS:
1.UNCONTROLLED TRIALS
2.NATURAL EXPERIMENTS/ QUASI TRIALS
3.BEFORE AND AFTER COMPARISON STUDIES
1.CLINICAL TRIALS
2.PREVENTIVE TRIALS
3.RISK FACTOR TRIALS
4.CESSATION EXPERIMENTS
5.TRIAL OF AETIOLOGICAL AGENTS
6.EVALUATION OF HEALTH SERVICES
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

27. Select suitable population
(Reference or Target Population)
Select suitable sample
(Experimental or study population)
Those not eligible
Those who do not
wish to give consent
Make necessary exclusions
RANDOMIZE
Experimental group Control Group
Manipulation & Follow up
Assessment
DESIGN OF A RANDOMIZED CONTROLLED TRIAL

28. CROSS-SECTIONAL STUDYLONGITUDINAL STUDY
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

29. Patients
Random Assignment
Exposed to
Specific Treatment
Unexposed to
Specific Treatment
Observation
Compare
Outcome
Compare
Outcome
Exposed &
Unexposed
to treatment
CONCURRENT PARALLEL STUDY DESIGN
CROSS-OVER TYPE OF STUDY DESIGN
Time
Patients
Random Assignment Observation
Time
Exposed to
Specific Treatment
Unexposed to
Specific Treatment

30. BIAS
BIAS IS A SYSTEMATIC ERROR IN THE DETERMINATION OF THE
ASSOCIATION BETWEEN THE EXPOSURE AND DISEASE.
It is an influence that produces distortion in the study results.
It cannot be eliminated completely but it can be marginalized by
1. Matching
2. Randomization
3. Blinding.
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
Selection Bias
Recall Bias
Publication/Reporting Bias
Funding Bias
Berksonion Bias
Surveillance Bias
Interviewer Bias
Types

31. 31
Get an Idea
Turning research problem to Research question
Translate it into a working hypothesis
Review the relevant Literature
Realistically evaluate what you are about to do
i.e. preparing the research designs
Determine the sample design
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
Procedural steps in doing RESEARCH

32. Write a protocol
Submit it to IRB and
then to university
Design and conduct Research
Analyze the data
Hypothesis testing
Draw conclusions
Generalization and Interpretation Preparation of report
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
Procedural steps in doing RESEARCH

33. Vipeholm Dental caries study (1954)
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS
Ethical Issues in Scientific Research

34. ProtectingHuman
Subjects
Treating subjects
Fairly
Treating subjects
Equally
Three goals of research ethics
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

35. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

36. What should an Informed Consent should contain?
•Aimsoftheresearch
•Durationofparticipation
•Proceduresemployed
•Risks&discomforts
•Benefits
•Alternativeprocedures
•Privacy&confidentiality
•Compensation
•Availabilityofmedical
treatmentsifinjuryoccurs
•Whomtocontact
•VoluntaryParticipation
•May discontinue
participationatanytime
withoutpenalty
•Authorizationtopublish
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

37. •Chair person –should be from
outside the institution
•Member Secretary from the
institution
•One legal expert or retired judge
•1-2 basic medical scientists
•1-2 clinicians from various
institutes
•One social
scientist/representative of NG
voluntary agency
•One
philosopher/ethicist/theologian
•One lay person
•If required, subject experts
could be invited to offer views
Members of IRB
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

38. 1.OutrightapprovalAt most, only very minor changes are
suggested. The application contained all necessary
information .
2. Approvalwith modificationsThere is enough information
to judge the study, but clarification or changes are needed.
Decision of IRB
3. Resubmit with more informationThere is not enough
information to judge the application appropriately.
4. Outright disapprovalThere is no way the researcher can
ethically do the study.
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

39. veerannaramesh
@gmail.com
Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS

40. Dr Veeranna Ramesh, Public Health Dentist,
Faculty of Dental Sciences, MSRUAS