Hiding research results should always be treated as though the results were very negative. There are many reasons that a study might get cancelled that are unre

Hiding research results should always be treated as though the results were very negative. There are many reasons that a study might get cancelled that are unrelated to business interests (like breaking of blinds or various other methodological reasons why a study's data is corrupted), and it's okay(ish) to not publish these results -- there are no good protocols for publishing data about a study's failure, but it would be nice to develop those. But without knowing the reason for the failure to publish the study, it should be assumed that the results provide negative evidence for all hypotheses. Pre-registration is supposed to solve this problem by listing the studies before they are conducted so that it is impossible to completely elide them. A drug approval would then look at all studies pre-registered for the treatment, and only at those studies pre-registered for the treatment -- whether those studies were complete or not.