---
title: Attrition
description: Technical term used in research that involves repeated assessments including the whole field of repeated measures across therapy. It covers all the loss of participants from the study as time goes by. In studies across the duration of therapies it…
url: "https://www.psyctc.org/psyctc/glossary2/attrition/"
updated: "2024-10-11"
category: All OM book glossary entries
---

# Attrition

Technical term used in research that involves repeated assessments including the whole field of repeated measures across therapy. It covers all the loss of participants from the study as time goes by. In studies across the duration of therapies it almost always becomes dominated what is often called "dropping out" which I think should be called "opting out". However, other factors can lead to attrition and it is a term used across much more that therapy studies.

#### Try also

["Dropping out"](https://www.psyctc.org/psyctc/glossary2/dropping-out/)
["Opting out"](https://www.psyctc.org/psyctc/glossary2/opting-out/)
[Repeated measures](https://www.psyctc.org/psyctc/glossary2/repeated-measures-tests/)

#### Chapters

One of the topics of interest in chapter 7.

#### Online resources

None yet.

#### Dates

Created 15.viii.23, much improved 11.x.24.