This level of risk is called the significance. The process of data dredging involves testing multiple hypotheses using a single data set by exhaustively searching-perhaps for combinations of variables that might show a correlation, and perhaps for groups of cases or observations that show differences in their mean or in their breakdown by some other variable.Ĭonventional tests of statistical significance are based on the probability that a particular result would arise if chance alone were at work, and necessarily accept some risk of mistaken conclusions of a certain type (mistaken rejections of the null hypothesis). This is done by performing many statistical tests on the data and only reporting those that come back with significant results. JSTOR ( October 2016) ( Learn how and when to remove this template message)Ī humorous example of a result produced by data dredging, showing a coincidental correlation between the number of letters in Scripps National Spelling Bee's winning word and the number of people in the United States killed by venomous spiders.ĭata dredging (also known as data snooping or p-hacking) is the misuse of data analysis to find patterns in data that can be presented as statistically significant, thus dramatically increasing and understating the risk of false positives.Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.

Meaning of dredging