# Measure whether the AI helps

> A built-in A/B holdout serves some respondents a static form so you can compare completion and answer depth.

_Adaptive intake · forms.ax help · updated 2026-07-18 · https://forms.ax/help/adaptive/measure-impact_

## Ask your assistant

- "Analyze my form - is the adaptive group completing more and writing better answers than the holdout?"

Turn on a holdout fraction and that share of respondents get the plain static form — no follow-ups. `analyze_responses` then reports the two groups side by side: completion rate, drop-off, and answer depth.

Ask for it in one line: "give 20% of respondents the static version so we can compare." Turn it off the same way. Assignment is deterministic and PII-free.

## FAQ

**How is the holdout assigned?**
Deterministically per response — stable for a respondent's session, independent of any personal data, and off by default until you set a fraction.

Related: [analyze_responses](https://forms.ax/help/tools/analyze_responses) · [summarize_responses](https://forms.ax/help/tools/summarize_responses)