When power calculations won’t do: Fermi approximation of animal numbers

All animal protocols need quantitative justification of animal numbers, but not all will need power calculations.

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Fig. 1: Animal numbers decision tree.

References

  1. 1.

    The IACUC Handbook 3rd edn (ed. Silverman, J., Suckow, M. & Murthy, S.) (CRC Press, Boca Raton, 2014).

  2. 2.

    Institute for Laboratory Animal Research. Guide for the Care and Use of Laboratory Animals 8th edn (National Academies Press, Washington, DC, 2011).

  3. 3.

    Fitzpatrick, B. G., Koustova, E. & Wang, Y. Lab Animal (NY) 47, 175–177 (2018).

    Article  Google Scholar 

  4. 4.

    Weinstein, L. & Adam, J.A. Guesstimation: Solving the World's Problems on the Back of a Cocktail Napkin (Princeton University Press, Princeton, NJ, 2008).

  5. 5.

    von Baeyer, H.C. The Fermi solution in The Fermi Solution: Essays on Science pp 3-12 (Dover Publications, Inc., New York, 2001).

  6. 6.

    Fermi, E. My observations during the explosion at Trinity on july 16, 1945 - E. Fermi. Record Group 227, OSRD-S1 Committee, Box 82 Folder 6, “Trinity.” U.S. National Archives (1945), http://nuclearfiles.org/menu/key-issues/nuclear-weapons/history/pre-cold-war/manhattan-project/trinity/eyewitness-enrico-fermi_1945-07-16.htm

  7. 7.

    Kimmelman, J., Mogil, J. S. & Dirnagl, U. PLoS Biol. 12, e1001863 (2014).

    Article  Google Scholar 

  8. 8.

    Gosselin, R.-D. Lab. Anim. 53, 28–42 (2018).

    Article  Google Scholar 

  9. 9.

    Jung, S. H. & Young, S. S. J. Biopharm. Stat. 22, 30–42 (2012).

    Article  Google Scholar 

  10. 10.

    Johnson, D. H. J. Wildlife Management 66, 272–276 (2002).

    Article  Google Scholar 

  11. 11.

    Anderson, D. R., Burnham, K. P. & Thompson, W. L. J. Wildlife Management 64, 912–923 (2000).

    Article  Google Scholar 

  12. 12.

    Pitts, M. (ed.) Institutional Animal Care and Use Committee Guidebook, 210 pp. (Office of Laboratory Animal Welfare, National Institutes of Health, Bethesda, MD, 2002).

  13. 13.

    Eldridge, S. M. et al. PLoS One 11, e0150205 (2016).

    Article  Google Scholar 

  14. 14.

    Arain, M., Campbell, M. J., Cooper, C. L. & Lancaster, G. A. BMC Med. Res. Methodol. 10, 67 (2010).

    Article  Google Scholar 

  15. 15.

    Bowen, D. J. et al. Am. J. Prev. Med. 36, 452–457 (2009).

    Article  Google Scholar 

  16. 16.

    Festing, M. F. W. & Altman, D. G. ILAR J. 432, 244–258 (2002).

    Article  Google Scholar 

  17. 17.

    Kistin, C. & Silverstein, M. 314, 1561–1562 (2015).

  18. 18.

    Moore, C. G., Carter, R. E., Nietert, P. J. & Stewart, P. W. Clin. Transl. Sci. 4, 332–337 (2011).

    Article  Google Scholar 

  19. 19.

    Lancaster, G. A., Dodd, S. & Williamson, P. R. J. Eval. Clin. Pract. 10, 307–312 (2004).

    Article  Google Scholar 

  20. 20.

    Whitehead, A. L., Julious, S. A., Cooper, C. L. & Campbell, M. J. Stat. Methods Med. Res. 25, 1057–1063 (2016).

    Article  Google Scholar 

  21. 21.

    Dell, R. B., Holleran, S. & Ramakrishnan, R. ILAR J. 43, 207–213 (2002).

    CAS  Article  Google Scholar 

  22. 22.

    Altman, D.G., et al. Why do a pilot study? NC3Rs: National Centre for the Replacement, Refinement and Reduction of Animals in Research, 2 pp. (2006).

  23. 23.

    Reynolds, P.S., et al. Lab. Anim. https://doi.org/10.1177/0023677218802999 (2018).

    Article  Google Scholar 

  24. 24.

    van Belle, G. Statistical Rules of Thumb (John Wiley & Sons Inc, Hoboken NJ, 2008).

  25. 25.

    Landis, S. C. et al. Nature 490, 187–191 (2012).

    CAS  Article  Google Scholar 

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Acknowledgements

The author thanks C. Garvan and T. Vasilopoulos (Statistics in Anesthesiology Research (STAR) Core, University of Florida, USA) for their helpful comments on an earlier version of this manuscript.

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Correspondence to Penny S. Reynolds.

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The author declares no competing interests. The author discloses membership with the University of Florida IACUC committee.

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Reynolds, P.S. When power calculations won’t do: Fermi approximation of animal numbers. Lab Anim 48, 249–253 (2019). https://doi.org/10.1038/s41684-019-0370-2

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Further reading

  • Reporting animal research: Explanation and elaboration for the ARRIVE guidelines 2.0

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