This document discusses study designs in clinical trials. It defines a study design as a specific plan or protocol for conducting a study. There are two main types of study designs: observational studies and experimental studies. Observational studies observe subjects and have no active intervention, while experimental studies manipulate variables under controlled conditions. Some fundamental study designs discussed include randomized controlled trials, cohort studies, case-control studies, case reports, and case series. The conclusion is that a study design should be a highly specific plan to be followed without deviation to achieve the research purpose.

1. Welcome
STUDY DESIGNS IN CLINICAL TRIALS
VISHNU. S
B PHARM
CSRPL_INT_ONL_WKD_139/0722
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2. Index
• What is study design?
• Research design
• Fundamental types
• Conclusion
• Reference
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3. WHAT IS A STUDY DESIGN ?
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▪ A specific plan or protocol for conducting the study
▪ Allows the investigator to translate the conceptual
hypothesis into a operational one

4. RESEARCH DESIGN
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SAMPLING
DESIGN
OBSERVATIONAL
DESIGN
STATISTICAL
DESIGN
OPERATIONAL
DESIGN

5. FUNDAMENTAL TYPES
• Distinguished by the methods in which subjects are subjected to the
treatment
• Should follow the 3 criteria :
I. Test the hypothesis properly
II. Control for extraneous variables like bias, confounders and
sampling errors
III. Allow generalization of results of the study to the population
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Does the investigator
assign exposure ?
Yes No
Experimental study
Human Animal
In-vitro In-vivo
Ex-vivo
NON-RCT
RCT
Observational study
Individual Population
Descriptive
Analytical

7. Observational studies
• ‘Any study that is not truly experimental’
• Provide information about naturally occurring health status, behavior,
attitudes or other characteristics of a particular group
• Observation of distribution of a disease in community with reference to time,
place and person.
• Subjects are observed and no active intervention .
• Is of two types:
Descriptivestudy
Analytical study
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8. DESCRIPTIVE STUDY
• Describes the various characteristics of the study without
causation
• Key features - Absence of comparison group and non- intervention
• Helps in describing ADR occurrence in patients
• Conducted disease is new or rare and is much not known about
the etiology , symptoms and disease characteristics.
• They are of three types
CASE REPORT
CASE SERIES
SURVEYS
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9. • Case Report
reports of events and individual patient experience on drug exposure and
outcome observed in single patient.
It is not ordinarily used to make a statement on causation of an event , but it gives
signal that can make others alert to the possibility of causal association.
Example: best classical example of a case report was that of Dr.William Mc Bride ,
report indicating that thalidomide might be a human teratogen .
• Case series
collection of individual case reports(multiple patients with the same findings)
no control group involved
• Surveys
collection of information from a group , can be demographic, opinions,
knowledge and behaviors.
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10. Analytical studies
• Studies used to test hypothesis concerning the relationship between
a suspected risk factor and an outcome and to measure the
magnitude of the association and its statistical significance.
COHORT STUDY:
starts with exposure (risk factor) and follow for the
outcome(disease). Consist of two groups:
first group – exposed to some risk
second group – free from exposure
CASE CONTROL STUDY
a retrospective study , study start with outcome and search for risk
factors by taking case records.
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11. • Cross – sectional study
measures exposure and outcome at the same time in randomly
selected population.
No follow up required
Used to assess prevalence of disease
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12. EXPERIMENTAL STUDIES
• Set of observations , conducted under controlled
circumstances , manipulated in order to check the effect of
such manipulations .
• Consists of two types :
Animal studies
a) In vitro
b) In vivo
c) Ex vivo
Human studies
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13. RANDOMIZED CONTROLLEDTRIAL
• Most effective method of determining cause effect relationship
• Subjects are allocate randomly in to experimental and control group
• Randomization is known to be the heart of RCT
simple randomization
block randomization
stratified randomization
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14. CONCLUSION
Study design should be highly specific plan that is to be
followed without deviation in order to bring in relevance to the
research purpose.
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15. REFERENCES
• Clinical trials Steven piantadosi et al , 2017
• Adaptive design – clinical trials, methodology, challenges and
prospect, Rajiv mahajan et al
• Coffey Cs et al clinical trials , progress and challenges .Drugs
RD.2008;9:229-42
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16. ThankYou!
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