At what significance level do most statistical tests operate?

The significance level that most statistical tests commonly operate at is 0.05. This threshold is a convention in many fields of research, including psychology, for determining whether to reject the null hypothesis. When the p-value obtained from a statistical test is less than 0.05, researchers can conclude that there is a statistically significant effect, allowing them to infer that the results are unlikely to have occurred by chance.

Using a significance level of 0.05 strikes a balance between being too lenient (which could lead to Type I errors, or false positives) and too strict (which could result in Type II errors, or false negatives). It allows researchers to conduct hypothesis tests efficiently while maintaining a reasonable level of error. This level is widely accepted and facilitates consistency across studies, making it easier to compare results within the field.

While other significance levels, such as 0.01 or 0.10, can be used in specific situations based on the context of the study or the accepted rigor of the field, 0.05 remains the most widely utilized in general psychological research.