Core Competencies:
Choosing Study Design
Dr. Jackson K. Mukonzo, MSc. Pharm, Ph.D
Before starting……..
• Is there a problem? – Do you have a research question?
• What do you want to do about the problem?
• How do you want to do it?
Research Design
Research Design refers to the plan, structure, and strategy of
research--the blueprint that will guide the research process.
Intriguing Observation,
Intellectual Curiosity
Refinement of theory
(Inductive Reasoning)
More Careful Studying
of the Phenomenon
Defining Research
Problem & Objectives
THE PROCESS OF
Building the Theoretical
Framework and the
Research Model
EMPIRICAL RESEARCH
Testing Hypo.:
Data Analysis &
Interpretation
Developing Research
Hypotheses
Data Coding,
And
Editing
Developing Operational
Definitions for
Research Variables
Data Collection
Sampling Design
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Study design: How?
A study design is a specific plan or protocol for
conducting the study, which allows the investigator to
translate the conceptual hypothesis into an operational
one.
Choice of Design
• Research Question(s)
• Research Goal(s)
• Researcher Beliefs and
Values
• Researcher Skills
• Time and Funds
• Ethical Limitations
• Status of Existent Knowledge
• Occurrence of Disease
• Duration of Latent Period
• Nature and Availability of
Information
• Available Resources
Types of Study Designs
• Qualitative
• Quantitative
• Experimental
• Observational
• Basic
• Hybrid
• Incomplete
Qualitative
Quantitative
• Are you interested in meaning of
experiences or just describing?
• Understanding -words and anlysis
• Real world experience
• Open-ended and flexible rich data
• Quality of informant more
important than sample size
• Subjective
• Prediction- discrete
• Theory testing (experimental)
• Sample size core issue in reliability
of data
• What you plan for is what get
• Objective
Is any of the methods better than the other?
No!
Qualitative Techniques
• Participant observation
• Gains insight into understanding cultural patterns to
determine what’s necessary and needed in tool
development (complementary to interviews)
• Interviews/Focus groups with stakeholders
• Explores how tools are used and could be used in a novice
programming course
• Gains insight into the meaning of tools for students for
learning to program
Quantitative Designs
Analytical
Experimental
Descriptive
Observational
Community Survey
Randomized
Clinical Trial
Cohort
Non-randomized
Clinical Trial
Cross-sectional
Case-control
Other
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Analytic Studies
• We can use analytical studies to test hypotheses.
• We want to know:
• Whether there is an association between hypothesized exposure
and disease,
• How strong the association is,
• What proportion of cases are due to exposure, and
• Whether there is an increased risk of disease with increased
exposure (a dose-response relationship).
• Experimental or observational
Quantitative designs
• Observational: studies that do not involve any
intervention.
• Experimental: studies that entail manipulation of the
study factor (exposure) and randomization of subjects
to treatment (exposure) groups
Quantitative Designs
Analytic
Experimental
Descriptive
Observational
Community Survey
Randomized
Clinical Trial
Cohort
Non-randomized
Clinical Trial
Cross-sectional
Case-control
Other
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outcome
RANDOMIZATION
Intervention
no outcome
Study
population
outcome
Control
no outcome
baseline
future
time
Study begins here (baseline point)
Think more, Think Well, It Can be Easier!
One of the simplest experimental designs is the ONE GROUP PRETESTPOSTTEST DESIGN--EXAMPLE?
One way to examine Efficacy of a Drug:
O1
Measure
Patients’ Condition
(Pretest)
X
DRUG
Experimental
Condition/
intervention
O2
Measure
Patients’ Condition
(Posttest)
• RESULT: Significant Improvement from O1 to O2 (i.e., sig. O2 - O1
difference)
• QUESTION: Did X (the drug) cause the improvement?
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Research question 1:
Does perinatal exposure to TDF have any effect on bone
development during the first 10 years of life?
Study design?
Research question 2:
Does the use of a particular vaginal microbicide ring during
pregnancy have any effect(s) on birth outcomes?
Study design?
Research question 3
Why is the up-take of contraceptive formulation X low in women ≤
30 years of age
Study design?
Questions or Comments
?
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