A Guide to Sample Size for Animal-based Studies

Animal-based research poses a unique set of experimental design challenges. The most important of these are the 3Rs - Replacement, Reduction and Refinement - the principles comprising the ethical framework for humane animal-based studies. However, many researchers have difficulty navigating the design trade-offs necessary to simultaneously minimise animal use, and produce scientific information that is both rigorous and reliable.

A Guide to Sample Size for Animal-based Studies meets this need with a thorough, accessible reference work to the subject. This book provides a straightforward systematic approach to "rightsizing" animal-based experiments, with sample size estimates based on the fundamentals of statistical thinking: structured research questions, variation control and appropriate design of experiments. The result is a much-needed guide to planning animal-based experiments to ensure scientifically valid and reliable results.

This book offers:
* Step-by-step guidance in diverse methods for approximating and refining sample size
* Detailed treatment of research topics specific to animal-based research, including pilot, feasibility and proof-of-concept studies
* Sample size approximation methods for different types of data - binary, continuous, ordinal, time to event - and different study types - description, comparison, nested designs, reference interval construction and dose-response studies
* Numerous worked examples, using real data from published papers, together with SAS and R code

The book is suitable for preclinical and veterinary researchers, ethical oversight committees and policymakers.

Penny S. Reynolds, PhD, is a Research Assistant Professor in the Department of Anesthesiology, College of Medicine, and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, USA.

First edition, September 2023. 288 Pages, Softcover.

Content:

Preface

Acknowledgements

Part I. What is sample size?

1. Introduction: The sample size problem in animal-based research

2. Sample size basics

3. Ten strategies to increase information (and reduce animal numbers)

Part II. Sample size for feasibility and pilot studies

4. Introduction to pilot studies

5. Operational pilots

6. Empirical and translational pilots

7. Feasibility calculations: Arithmetic estimation

8. Feasibility calculations: Probability-based estimation

Part III. Sample size for description

9. Introduction to descriptive studies

10. Confidence intervals

11. Prediction intervals

12. Tolerance intervals

13. Reference intervals

Part IV. Sample size for comparison

14. Hypothesis testing, power, non-centrality

15. A bestiary of effect sizes

16. Comparing two groups: Continuous outcomes

17. Comparing two groups: Binary and count outcomes

18. Comparing two groups: Time to event outcomes

19. Comparing multiple factors

20. Multi-level and hierarchical designs

21. Ordinal data

22. Dose-response studies

Index