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PLoS Biol. 2016 Jan 4;14(1):e1002331. doi: 10.1371/journal.pbio.1002331. eCollection 2016 Jan.

Where Have All the Rodents Gone? The Effects of Attrition in Experimental Research on Cancer and Stroke.

Author information

1
Medical Neurosciences Program, Charité Universitätsmedizin Berlin, Berlin, Germany.
2
NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany.
3
Center for Stroke Research, Charité Universitätsmedizin Berlin, Berlin, Germany.
4
Department for Biostatistics and Clinical Epidemiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
5
Biomedical Ethics Unit, McGill University, Montréal, Canada.
6
Department of Experimental Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany.
7
German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.
8
Berlin Institute of Health, Berlin, Germany.

Abstract

Given small sample sizes, loss of animals in preclinical experiments can dramatically alter results. However, effects of attrition on distortion of results are unknown. We used a simulation study to analyze the effects of random and biased attrition. As expected, random loss of samples decreased statistical power, but biased removal, including that of outliers, dramatically increased probability of false positive results. Next, we performed a meta-analysis of animal reporting and attrition in stroke and cancer. Most papers did not adequately report attrition, and extrapolating from the results of the simulation data, we suggest that their effect sizes were likely overestimated.

PMID:
26726833
PMCID:
PMC4699644
DOI:
10.1371/journal.pbio.1002331
[Indexed for MEDLINE]
Free PMC Article

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