A reproducibility crisis is a situation where many scientific studies cannot be reproduced. Inappropriate practices of science, such as HARKing, p-hacking, and selective reporting of positive results, have been suggested as causes of irreproducibility. In this editorial, I propose that a lack of raw data or data fabrication is another possible cause of irreproducibility.
As an Editor-in-Chief of Molecular Brain, I have handled 180 manuscripts since early 2017 and have made 41 editorial decisions categorized as “Revise before review,” requesting that the authors provide raw data. Surprisingly, among those 41 manuscripts, 21 were withdrawn without providing raw data, indicating that requiring raw data drove away more than half of the manuscripts. I rejected 19 out of the remaining 20 manuscripts because of insufficient raw data. Thus, more than 97% of the 41 manuscripts did not present the raw data supporting their results when requested by an editor, suggesting a possibility that the raw data did not exist from the beginning, at least in some portions of these cases.
Considering that any scientific study should be based on raw data, and that data storage space should no longer be a challenge, journals, in principle, should try to have their authors publicize raw data in a public database or journal site upon the publication of the paper to increase reproducibility of the published results and to increase public trust in science.
The reproducibility or replicability crisis is a serious issue in which many scientific studies are difficult to reproduce or replicate. It is reported that, in the field of cancer research, only about 20–25%  or 11%  of published studies could be validated or reproduced, and that only about 36% were reproduced in the field of psychology . Inappropriate practices of science, such as HARKing (Hypothesizing After the Results are Known) , p-hacking , selective reporting of positive results and poor research design [6,7,8], have been proposed to be a cause of such irreproducibility. Here, I argue that a lack of raw data is another serious possible cause of irreproducibility, by showing the results of analyses on the manuscripts that I have handled over the last 2 years for Molecular Brain. The analysis shows that many researchers did not provide the raw data, suggesting that raw data may not exist in some cases and that the lack of data may constitute a non-negligible part of the causes of the reproducibility crisis . In this editorial, I argue that making raw data openly available is not only important for reuse and data mining but also for simply confirming that the results presented in the paper are truly based on actual data. With such concept, the data sharing policy of Molecular Brain has been changed and I introduce this update.
Raw data rarely comes out
As Editor-in-Chief of the journal, I have handled 180 manuscripts since early 2017 to September 2019 and have made 41 editorial decisions categorized as ‘Revise before review’, with comments asking the authors to provide raw data (Fig. 1; See Additional file 2: Table S1 for details).
Flowchart of the manuscripts handled by Tsuyoshi Miyakawa in Molecular Brain from December 2017 to September 2019