1. Why Performed ?
Provide stronger evidence of the effect (outcome) compared to observational designs, with maximum confidence and assurance
Yield more valid results, as variation is minimized and bias controlled
Determine whether experimental treatments are safe and effective under “controlled environments” (as opposed to “natural settings” in observational designs), especially
when the margin of expected benefit is doubtful / narrow ( %)

2. Experimental Design time outcome Intervention no outcome Study
RANDOMIZATION
Intervention
no outcome
Study
population
outcome
Control
no outcome
Experimental Design
baseline
future
time
Study begins here (baseline point)

3. Types of trials

4. RCT Advantages (I)
the “gold standard” of research designs. They thus provide the most convincing evidence of relationship between exposure and effect. Example:
trials of hormone replacement therapy in menopausal women found no protection for heart disease, contradicting findings of prior observational studies

5. RCT Advantages (II) Best evidence study design
No inclusion bias (using blinding)
Controlling for possible confounders
Comparable Groups (using randomization)

6. RCT Disadvantages
Large trials (may affect statistical power)
Long term follow-up (possible losses)
Compliance
Expensive
Public health perspective ?
Possible ethical questions

7. Quasi-Experimental Designs
Groups or subjects not randomly assigned
e.g., sample of convenience
May not have a comparison group
Typical of clinical research
e.g., within subjects repeated measures
Less “subject-intensive”

8. Broad Distinctions Between subjects Within subjects Mixed
Dependent measures taken one time
Data are independent (i.e., not correlated)
Within subjects
A “repeated measures” design
Dependent measures taken multiple times
Data are dependent
Mixed
Between and within

9. Design Types Single factor (one-way) Multi-factor Time-series
Studies one independent variable
Multi-factor
Studies multiple independent variables
May have several levels
Examples:
Two-way (e.g., 2 x 2)
Three-way (e.g., 2 x 2 x 2)
Time-series

10. Single Factor Designs Pretest-posttest (one-group)
Pretest-posttest (control group)
Posttest-only (control group)

11. Pretest-Posttest (one group)
Quasi-experimental
One set of measures taken before and after treatment or intervention
Compare pretest and posttest scores
Analysis
paired t test
Weakness
No comparison or control group

12. Pretest-Posttest (control group)
Experimental design - random assignment
Two groups
Control
Experimental
Measures on dependent variable made on both groups pre- and posttest
Significant differences in experimental group not found in control group attributable to treatment
Analysis
difference scores compared with independent t test
ANCOVA pretest score as covariate

13. Multiple Factor Designs
Two-way factorial
e.g., 2 x 3
Three-way factorial
e.g., 2 x 2 x 3

14. Two-Way Factorial Design
Studies multiple independent variables
Main effects (ME)
Each with a number of levels (L)
Permits study of interactions
Analysis
ANOVA
Example: 2 x 3
ME2
L1 L2 L3 L1
ME1 L2

15. Three-Way Factorial Design
Studies multiple independent variables
Main effects (ME)
Multiple levels (L)
Interactions effects
Analysis
ANOVA
Post hoc pairwise comparisons
Example 2 x 2 x 3
ME 2 L2 L1 L1
ME1 L2
L1 L2 L3
ME3

16. Counterbalanced Design
Possibility of order effects biasing data in a repeated measures design
Solutions
Randomize order
Counterbalance trials - order systematically varied
Example - two treatments (T1 - T2) “Crossover design”
Half of subjects - T1 then T2
Half of subjects - T2 then T1

17. Latin Square Design Minimizes order effects Test session 1 2 3
Subject 1
Subject 2
Subject 3
A B C
B C A
C A B

18. Single Subject Design
Permits analysis of effects of treatment in individual subjects (or groups)
Elements
Subjects usually own control
Repeated measures
Design phases (times series analysis)

19. Single Subject Design Time series analysis
Dependent measure is continuous
Establish baseline
Measure treatment effect over time
Baseline
Treatment
Time

20. Case Report Subject a single individual Often uses a narrative format
May be non-experimental or experimental
Develops a profile of the subject using:
Visual observation
Interviews/surveys/questionnaires
Objective data
May provide generalizations about other subjects with similar conditions

21. Researcher Beliefs and Values Researcher Skills Time and Funds
Choice of Design (I)
Depends on:
Research Questions
Research Goals
Researcher Beliefs and Values
Researcher Skills
Time and Funds

22. Choice of design (II) It is also related to:
Status of existent knowledge
Occurrence of disease
Duration of latent period
Nature and availability of information
Available resources

23. Comparing study designs
Theme
Ease
Timing
Maintenance and continuity
Costs
Ethics
Data utilisation
Main contribution
Observer bias
Selection bias
Analytic output

24. Overlap in the conceptual basis of quantitative study designs
The cross-sectional study can be repeated
If the same sample is studied for a second time i.e. it is followed up, the original cross-sectional study now becomes a cohort study.
If, during a cohort study, possibly in a subgroup, the investigator imposes an intervention, a trial begins.
Cohort study also gives birth to case-control studies, using incident cases (nested case control study).
Cases in a case-series, particularly a population based one, may be the starting point of a case-control study or a trial.
Not every epidemiological study fits neatly into one of the basic designs.

25. Conclusion (I)
Qualitative designs are complementary to quantitative designs, are important in study of social determinants of health problems
Quantitative designs have a common goal to understand the frequency and causes of health-related phenomena
Seeking causes starts by describing associations between exposures (causes) and outcomes

26. Conclusion (II)
Case-series is a coherent set of cases of a disease (or similar problem).
Cases are compared with reference group, we have a case control study
In a population studied at a specific time and place (a cross-section) the primary output is prevalence data, though association between risk factors and disease can be generated.
In cross-sectional studies, we are looking for both exposure and outcome
In case-control studies, we know the outcome, looking for the exposure
In cohort studies, we know the outcome, following up looking for the outcome in question

27. Conclusion (III)
If the population in a cross-sectional survey is followed up to measure health outcomes, this study design is a cohort study.
If the population of such a study are, at baseline, divided into two groups, and the investigators impose a health intervention upon one of the groups the design is that of a trial.
Studies based on aggregated data are commonly referred to as ecological studies.
Mostly, ecological studies are mode of analysis, rather than a design.
Interpretation and application of data are easier when the relationship between the population observed and the target population is understood
RCTs represent the “gold standard” of research designs. They thus provide the most convincing evidence of relationship between exposure and effect..

28. References
Porta M. A dictionary of epidemiology. 5th edition. Oxford, New York: Oxford University Press, 2008.
Rothman J, Greenland S. Modern epidemiology. Second edition. Lippincott - Raven Publishers, 1998.
Bhopal R. Study design. University of Edinburgh.
NLM. An introduction to Clinical trials. U.S. National Library of Medicine, 2004
Songer T. Study designs in epidemiological research. In: South Asian Cardiovascular Research Methodology Workshop. Aga-Khan and Pittsburgh universities.

29. Proposal Writing

30. What is a research proposal?
A research proposal is your plan
It describes in detail your study
Decisions about your study are based on the quality of the proposal
Research funding
Approvals to proceed by the Institutional Review Board

31. Sections of the Proposal
Need
Summary
Budget
Plan
Method
Evaluate

32. Budget Your Time Communicate Solid partnerships Innovative project
Have your ducks in a row BEFORE you write a proposal – have your partnerships and budget as close to final as possible…and remember that Innovative projects will catch their attention
Innovative project
Define your budget
80% planning the project % writing the proposal

33. Avoid Plagiarism
Plagiarism is presenting someone else’s ideas or words as though they were your own.
DANGEROUS!!!!

34. Research Proposal Elements
Background/ significance
Research Question/Aim/Purpose
Methods
Design
Sample/Sample Size
Setting
Protocol
Analysis plan
Timeline

35. Background/ Significance
Why is your study important?
Describe the significance of the research question or problem
Answer the “so what?” question

36. Literature review
What is the state of the science/art on this problem? Are there gaps in the literature? How will your study fill those gaps?
Synthesize recent literature (within the past 5 years)

37. Purpose Identify simply what you plan to do in your study
The purpose can be framed as a research question or an aim
Examples:
What is the impact of meditative music on agitation in hospitalized elders?
The purpose of this study is to show the impact of meditative music on agitated elders.

38. Methods This section of your proposal has multiple parts
Design
Sample/Sample size
Setting
Protocol
Analysis Plan
Detailed enough so that the reviewers could conduct the study

39. Methods - Design Describe your study design Design examples Example
Prospective vs. Retrospective
Descriptive
Observation
Intervention clinical trial
Surveys, interviews, questionnaires
Focus groups, field studies
Others
Example
We plan a prospective randomized controlled trial of meditative music vs. no music

40. Methods – Sample/Sample Size
Who are the study participants?
Describe inclusion criteria
Example: Adult men and women inpatients with stage IV heart disease
Who is excluded?
Example: Patients who do not speak English

41. Methods – Sample cont’d
How will participants be recruited?
Convenience sample
Flyers in research offices
Advertisements
Electronic Records search
How many participants are needed?
How will you justify the sample size?
Has there been a power analysis?
Do you have a comparison or control group?

42. Setting Describe the sites where you plan to conduct the study
Do you have support from the administration of the site to conduct the study?
Letters of support from site

43. Protocol What are you going to do to study participants?
Detailed, step by step explanation
Include how you will identify participants, obtain consent, and collect data
If there is an intervention, describe it in detail
Will you use measurement tools? Describe the tools, including reliability and validity and include a copy of the tools with your proposal
Include the time frame for implementing the study

44. Data Analysis Describe your analysis plan
What statistical tests will you use?
Be sure your statistics are appropriate for your study design

45. Timeline Describe how long it will take to do your study
Provide timeline benchmarks
Example:
Months 1 – 3 Prepare study tools
Months 4-10 Collect data
Months Analyze data

46. Common pitfalls to avoid
Missing aims or purpose
Not enough detail about protocol
Write your proposal so anyone reading it can understand your plan
Is your study significant?
Does it answer the larger “So what” question? Why should researchers care about this work?
Underpowered sample size
Describe why you are using the sample size and justify it
Invalid or unreliable instrumentation
Has your instrument been tested with the population you are studying? If not, will you test it within your study?
Improper statistics
Are you using the appropriate statistical analysis?

47. Evaluation of proposals
Proposals reviewed based on specific criteria defined by the IRB
The research design must be sound enough to yield the expected knowledge
The aims/objectives are likely to be achievable in the given time period
The rationale for the proposed number of participants is reasonable
The scientific design is described and adequately justified

48. Factors to Consider 1 2 3 4 5 PRACTICAL CONSIDERATIONS HUMAN
COMPREHENSION 4
QUALITY 5
COMPETITIVE EDGE

49. Grants are important
Research grants are the dominant way for academic researchers to get resources to focus on research
INVARIANT: there is never enough money

50. The state of play
Even a strong proposal is in a lottery, but a weak one is certainly dead
Many research proposals are weak
Most weak proposals could be improved quite easily