# Survivorship Bias

*Math & Statistics — Finicade finance glossary*

Survivorship bias is measuring only the things that lasted long enough to be measured. Fund databases that drop closed funds overstate average returns by roughly one to two percentage points a year, because the failures vanish from the record. It shows up everywhere in finance: index histories that exclude delisted companies, strategy backtests run on today's constituents, and every 'habits of successful founders' study that never interviews the ones who failed.

**Also known as:** survivor bias, survivorship

**Related terms:** [Selection Bias](https://finicade.com/glossary/selection-bias), [Backtesting](https://finicade.com/glossary/backtesting), [Hedge Fund](https://finicade.com/glossary/hedge-fund), [Overfitting](https://finicade.com/glossary/overfitting), [Mutual Fund](https://finicade.com/glossary/mutual-fund)

Source: https://finicade.com/glossary/survivorship-bias