Position (rank) bias

Items higher in a ranked list get disproportionately more attention and clicks, whatever their true relevance.

Choice architecture Mainly on Search pages
Where it applies

Three of the eight page areas.

HomepageAlso applies CategoryAlso applies SearchMainly here ProductNot typical CartNot typical CheckoutNot typical Post-purchaseNot typical

Not usually a sitewide principle. See everything at work on Search pages

How to use it

Three ways to use it, and one to avoid.

  • Treat the default sort as the biggest merchandising decision on the results page.
  • Put best-match items in the top rows.
  • Don’t read raw click data as proof of relevance.
  • Avoid: presenting paid or margin-driven placement as organic relevance, which risks being a misleading practice.
What the research found

Rank drove clicks, but not purchases once an item was clicked.

In randomised Expedia rankings, rank drove clicks but not purchase once an item was clicked.

Ursu's randomised Expedia rankings showed that rank caused more clicks but did not change purchase once a hotel was clicked. Joachims and colleagues found searchers favoured the top result even when the order was secretly swapped. Ghose and colleagues found ranking by expected value to the shopper raised revenue, but on a test site with 900 paid participants.

Key research

Five sources, each checked.

Last reviewed

Joachims, Granka, Pan, Hembrooke & Gay (2005) Accurately interpreting clickthrough data as implicit feedback SIGIR Read the source Ursu (2018) The Power of Rankings: Quantifying the Effect of Rankings on Online Consumer Search and Purchase Decisions Marketing Science Read the source Ghose, Ipeirotis & Li (2014) Examining the Impact of Ranking on Consumer Behavior and Search Engine Revenue Management Science Read the source Craswell, Zoeter, Taylor & Ramsey (2008) An experimental comparison of click position-bias models WSDM Read the source Narayanan & Kalyanam (2015) Position Effects in Search Advertising and their Moderators: A Regression Discontinuity Approach Marketing Science Read the source
Before you use it · UK law

Paid or margin-driven placement presented as organic relevance risks being a misleading practice; get it checked before using sponsored ranking.

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