Autocomplete position bias

Searchers overwhelmingly look at and pick the top few query suggestions, so their order shapes what gets searched.

Attention and perception Mainly on Search pages
Where it applies

Two of the eight page areas.

HomepageNot typical CategoryNot typical SearchMainly here ProductNot typical CartNot typical CheckoutNot typical Post-purchaseNot typical

It also applies sitewide, on every page. See everything at work on Search pages

How to use it

Four ways to use it, and one to avoid.

  • Keep the suggestion list short.
  • Rank suggestions by how likely they are to lead to a successful result.
  • Make suggestions cope with misspellings.
  • Never suggest a query that returns nothing.
  • Avoid: sponsored suggestions presented as organic, which raise the same disclosure issue as paid ranking.
What the research found

Searchers favour the top suggestions, but the studies are web search, not ecommerce.

The evidence is eye-tracking and Bing log studies of web search, not ecommerce.

Hofmann and colleagues' eye-tracking study found a strong bias towards the top suggestions whatever the ranking quality. In Bing logs the second suggestion drew under 40% of the engagement of the first, and in Yahoo logs the top two took about 75% of clicks. All are web search; Baymard's ecommerce testing (industry) found most users picked from the first few.

Key research

Four sources, each checked.

Last reviewed

Hofmann, Mitra, Radlinski & Shokouhi (2014) An Eye-tracking Study of User Interactions with Query Auto Completion CIKM Read the source Mitra, Shokouhi, Radlinski & Hofmann (2014) On User Interactions with Query Auto-Completion SIGIR Read the source Scott (2022)Industry 9 UX Best Practice Design Patterns for Autocomplete Suggestions (Only 19% Get Everything Right) Baymard Institute Read the source Li, Dong, Wang, Deng, Chang & Zhai (2014) A Two-Dimensional Click Model for Query Auto-Completion SIGIR Read the source
Before you use it · UK law

Sponsored suggestions presented as organic raise the same disclosure issue as paid ranking.

This is simply a pointer to check, not legal advice. Seek legal advice before you put this principle into action.