Glossary
Survivorship Bias
What is survivorship bias?
Survivorship bias occurs when conclusions depend on the cases that remain visible while relevant cases that disappeared are left out. It is a form of selection bias.
Example
A study of historical fund performance that includes only funds still operating can miss the funds that closed. Brown and colleagues showed how this kind of selection can create apparent persistence in performance under specified conditions.
Why it matters
The survivors are only part of the story. Identify the original eligible group, find out what made some cases disappear, and check whether their outcomes are missing. Including discontinued or failed cases gives you a fuller comparison, though other sources of bias may remain.