The rankings are based on statistically significant results only (p < .05, two-tailed) because only statistically significant results can be used to interpret a result as evidence for an effect and against the null-hypothesis.  Published non-significant results are useful for meta-analysis and follow-up studies, but they provide insufficient information to draw statistical inferences.

The average power across the 105 psychology journals used for this ranking is 70%. This means that a representative sample of significant results in exact replication studies is expected to produce 70% significant results. The rankings for 2015 show variability across journals with average power estimates ranging from 84% to 54%.  A factor analysis of annual estimates for 2010-2015 showed that random year-to-year variability accounts for 2/3 of the variance and that 1/3 is explained by stable differences across journals.

The Journal Names are linked to figures that show the powergraphs of a journal for the years 2010-2014 and 2015. The figures provide additional information about the number of tests used, confidence intervals around the average estimate, and power estimates that estimate power including non-significant results even if these are not reported (the file-drawer).