Essential 10

3. Inclusion and exclusion criteria For each analysis, report the exact value of n in each experimental group. explanation


The exact number of experimental units analysed in each group (i.e. the n number) is essential information for the reader to interpret the analysis, it should be reported unambiguously. All animals and data used in the experiment should be accounted for in the data presented. Sometimes, for good reasons, animals may need to be excluded from a study (e.g. illness or mortality), or data points excluded from analyses (e.g. biologically implausible values). Reporting losses will help the reader to understand the experimental design process, replicate methods, and provide adequate tracking of animal numbers in a study, especially when sample size numbers in the analyses do not match the original group numbers.

For each outcome measure, indicate numbers clearly within the text or on figures, and provide absolute numbers (e.g. 10/20, not 50%). For studies where animals are measured at different time points, explicitly report the full description of which animals undergo measurement, and when [1].



  1. Vahidy F, Schäbitz W-R, Fisher M and Aronowski J (2016). Reporting standards for preclinical studies of stroke therapy. Stroke. doi: 10.1161/STROKEAHA.116.013643