Skip to main content Accessibility help
×
Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-24T00:00:14.504Z Has data issue: false hasContentIssue false

11 - Screening: A Pitfall in Statistics

Published online by Cambridge University Press:  03 February 2022

Timothy DelSole
Affiliation:
George Mason University, Virginia
Michael Tippett
Affiliation:
Columbia University, New York
Get access

Summary

Scientists often propose hypotheses based on patterns seen in data. However, if a scientist tests a hypothesis using the same data that suggested the hypothesis, then that scientist has violated a rule of science. The rule is: test hypotheses with independent data. This rule may sound so obvious as to be hardly worth mentioning. In fact, this mistake occurs frequently, especially when analyzing large data sets. Among the many pitfalls in statistics, screening is particularly serious. Screening is the process of evaluating a property for a large number of samples and then selecting samples in which that property is extreme. Screening is closely related to data fishing, data dredging, or data snooping. After a sample has been selected through screening, classical hypothesis tests exhibit selection bias. Quantifying the effect of screening often reveals that it creates biases that are substantially larger than one might guess. This chapter explains the concept of screening and illustrates it through examples from selecting predictors, interpreting correlation maps, and identifying change points.

Type
Chapter
Information
Publisher: Cambridge University Press
Print publication year: 2022

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×