02949nas a2200349   4500000000100000000000100001008003900002260001700041653001900058653001800077653002900095653002000124653001200144653002100156653003400177653002600211100001800237700002400255700001800279700002000297700001900317700001500336700001800351700001600369700001800385245013200403856007800535300001300613490000700626520195200633022001402585       0                             d  cAug 12, 202210aanimal studies10aBibliometrics10aClinical trial reporting10aclinical trials10aGermany10aResearch funding10aResearch reporting guidelines10aScientific publishing1 aTill Bruckner1 aSusanne Wieschowski1 aMiriam Heider1 aSusanne Deutsch1 aNatascha Drude1 aUlf Tölch1 aAndré Bleich1 aRené Tolba1 aDaniel Strech00aMeasurement challenges and causes of incomplete results reporting of biomedical animal studies: Results from an interview study  uhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.0271976  ae02719760 v173 aBackground Existing evidence indicates that a significant amount of biomedical research involving animals remains unpublished. At the same time, we lack standards for measuring the extent of results reporting in animal research. Publication rates may vary significantly depending on the level of measurement such as an entire animal study, individual experiments within a study, or the number of animals used. Methods Drawing on semi-structured interviews with 18 experts and qualitative content analysis, we investigated challenges and opportunities for the measurement of incomplete reporting of biomedical animal research with specific reference to the German situation. We further investigate causes of incomplete reporting. Results The in-depth expert interviews revealed several reasons for why incomplete reporting in animal research is difficult to measure at all levels under the current circumstances. While precise quantification based on regulatory approval documentation is feasible at the level of entire studies, measuring incomplete reporting at the more individual experiment and animal levels presents formidable challenges. Expert-interviews further identified six drivers of incomplete reporting of results in animal research. Four of these are well documented in other fields of research: a lack of incentives to report non-positive results, pressures to ‘deliver’ positive results, perceptions that some data do not add value, and commercial pressures. The fifth driver, reputational concerns, appears to be far more salient in animal research than in human clinical trials. The final driver, socio-political pressures, may be unique to the field. Discussion Stakeholders in animal research should collaborate to develop a clear conceptualisation of complete reporting in animal research, facilitate valid measurements of the phenomenon, and develop incentives and rewards to overcome the causes for incomplete reporting.  a1932-6203