Assessing the reporting and interpretation of non-significant results in the study of cognitive development: a systematic review

Null Hypothesis Significance Testing is a statistical procedure widely used in cognitive development research. There is widespread concern that the results of this statistical procedure are misinterpreted and lead to unsubstantiated claims about studies’ outcomes. Two particularly pertinent issues for research on cognitive development are: i) treating a non-significant result as evidence of no difference or no effect, and ii) treating a non-significant result in one group/condition and a significant result in another as evidence of a difference between groups/conditions. The current study focuses on quantifying the extent to which these two issues can be observed in the published literature on cognitive development. To this end, we will systematically search for empirical studies investigating cognitive development in 0-to-16-year-old children that have been published at two time points, namely in 1999 and 2019. For each of the two issues, we will extract information from 300 published articles, 150 per publication year.