Madlibs-style sign-up form vs standard form: -22% trial sign-ups
Commentary byLiftArchiveOur analysis, not theirsA madlibs-style registration form, where the fields sit inside a sentence, converted 21.73% of visitors to a free trial against 27.55% for the standard labeled form, about 22% worse.
Patrick McKenzie ran this test on Bingo Card Creator and published it on the Kalzumeus blog in 2010. Only the form style changed, and the result was significant at 95% confidence.
- Free trial sign-ups fell from 27.55% to 21.73% with the madlibs form, a relative drop of about 22%.
- The drop was significant at 95% confidence. The source notes the direction is reliable, not the exact size.
- 736 participants, split about 50/50, over 34 hours.
The change
Labeled form fields replaced by fields set inside a sentence.
Simplified mockup drawn by LiftArchive from the shared screenshots.
Control
A standard registration form with a label next to each field.
Variant
A madlibs-style form, with the input fields placed inside a written sentence. The fields themselves stayed the same.
Why it likely lost
Our reading of the result, not the practitioner's claim.
- A sign-up form is short and familiar, so a novel layout adds reading time without solving a real problem.
- Fields inside a sentence can be harder to scan, and it may be less clear what to type where.
- The madlibs idea spread from a lead-gen form test where about seven things changed at once, so the original lift may never have come from the sentence layout.
Caveats: The test ran for only 34 hours, and another A/B test was running on the same page at the same time. The data is from 2010.
Who ran it
Patrick McKenzie ran this test and published the results (Kalzumeus (patio11) blog). The numbers are theirs; the summary and commentary on this page are ours.
Read the original case study on Patrick McKenzie →
How to run this test on your site
- Hypothesis
- If we change our sign-up form to a madlibs-style sentence layout, then sign-ups will rise because the form feels more conversational, though a familiar form may be faster to fill in.
- Primary metric
- Free trial sign-up rate
- Guardrails
- Form error rate
- Time to complete the form
- Trial-to-paid conversion
- Who should test it
- Teams that are thinking about copying a trendy form style. Test it rather than assume it works. A short sign-up form with two or three fields probably has little to gain from a new layout.
Questions
Do madlibs-style forms increase conversions?
Not reliably. In this sign-up test, the madlibs form did about 22% worse than a standard form.
The famous win for madlibs came from a test that changed several things at once.
Should I copy A/B test results from other sites?
Use them as ideas for your own tests, not as proven fixes.
Your visitors, offer and form may behave differently.
How long should a sign-up form test run?
Until you reach a sample size you set in advance, ideally covering at least a full week.
This test stopped after 34 hours, which is short, though the gap was large.
MarketingExperiments