[INFOGRAPHIC] 15 Ways to Reduce Sample Size In Clinical Trials


Clinical trial costs have surged over the past decade, with recent reports stating that from 2008 to 2013, the average cost per patient increased by $23,600. A major contributor to the cost of a clinical trial is subject recruitment and the associated staff costs. So, examining every opportunity to reduce the sample size for a study is an important and necessary step in drug development.

Reducing sample size without losing power can be accomplished by one of three principles.

In this infographic, we examine these and present 15 ways researchers can reduce sample size in clinical trials.

15 Ways to Reduce Sample Size In Clinical Trials
# Method Potential Reduction
1 Adjust for Independent Variables in the Final Analysis 0 – 10%
2 Stratify the Patients 0 – 20%
3 Enrich the Patients 0 – 20%
4 Use Sustained Response 0 – 25%
5 Use Pairwise Comparisons 0 – 30%
6 Use Frequency Analysis 0 – 40%
7 Use Statistical Technique that Matches the Anticipated Response Curve 0 – 50%
8 Use Surrogate Endpoints 0 – 70%
9 Increase the Event Rate 0 – 90%
10 Run a Tight Clinical Trial 5 – 20%
11 Use Optimal Cut-Off for Binary Endpoint 10 – 30%
12 Use a Continuous Variable 10 – 40%
13 Use Adaptive Design 10 – 50%
14 Use Crossover Studies 50 – 70%
15 Use Factorial Designs 50 – 75%


Take a look at the extended guide on the nQuery Sample size Software website.

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About Author

Layla Tobin is part of the nQuery Sample Size Software team. In 2017, 90% of organisations with FDA approved clinical trials used nQuery for sample size calculation.

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