Consumer heterogeneity and paid search effectiveness: A large-scale field experiment
Blake, Nosko and Tadelis report a series of large-scale field experiments at eBay designed to measure the causal effect of paid search advertising. Because search clicks and purchase intent are correlated, returns from paid search turn out to be a fraction of non-experimental estimates. Brand keyword ads show no measurable short-term benefit. For non-brand keywords, new and infrequent users are positively influenced, but frequent users, whose purchasing the ads do not influence, account for most of the spending, so average returns are negative.
Blake, Nosko and Tadelis report a series of large-scale field experiments at eBay designed to measure the causal effect of paid search advertising. Because search clicks and purchase intent are correlated, returns from paid search turn out to be a fraction of non-experimental estimates. Brand keyword ads show no measurable short-term benefit. For non-brand keywords, new and infrequent users are positively influenced, but frequent users, whose purchasing the ads do not influence, account for most of the spending, so average returns are negative.
Written from the abstract as shown on the OpenAlex record, read 2026-11-04.
What our sources record
Recorded when this source was checked, figures included, with page references and quotation marks removed.
doi:10.3982/ECTA12423. NBER Working Paper 20171