History repeating: guidelines to address common problems in psychedelic science.

There are further problems, such as selectively removing outliers that result in significant findings, interpreting nonsignificant p -values in small samples as ‘trends toward significance’ (but not interpreting barely significant p -values as trends toward nonsignificance), and using one-sided tests over two-sided tests to obtain desired results, 30 discussed in Love. 38 All these problems jointly threaten both internal validity and statistical conclusion validity, as it remains unclear whether the conclusions are supported by the data and if other explanations might be more plausible for the effects observed.

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