>When did this become a "standard"? Most people would say in the 20s and point at Fischer's publications, though you can have arguments for later and earlier.

>When did this become a "standard"? Most people would say in the 20s and point at Fischer's publications, though you can have arguments for later and earlier. Some of that is mentioned in the Wiki page, and you can see 0.05 all over the article [0], and the other related wiki pages[1]. You can find some key quotes there: "The significance level for a study is chosen before data collection, and typically set to 5% or much lower, depending on the field of study" "In 1925, Ronald Fisher advanced the idea of statistical hypothesis testing, which he called "tests of significance", in his publication Statistical Methods for Research Workers. Fisher suggested a probability of one in twenty (0.05) as a convenient cutoff level to reject the null hypothesis.In a 1933 paper, Jerzy Neyman and Egon Pearson called this cutoff the significance level, which they named α." If you mostly see lower p-values, that most likely means that you usually read non-social science papers. I guarantee that most social science (and related) fields use 0.05 regardless of the respectability of the journal. As an example of fields with lower p-values - 0.001 is common in medicine, and physics commonly has even lower values. 0. https://en.wikipedia.org/wiki/P-value#History https://en.wikipedia.org/wiki/P-value#History 1. https://en.wikipedia.org/wiki/Statistical_significance#History https://en.wikipedia.org/wiki/Statistical_significance#Histo...