Injunctive Norms Outperform Reciprocity: Tip Request Messages Can Increase Tipping Without Reducing Demand

Tip request messages are marketing communications that can help digital platforms balance customer spending with worker effort and compensation. We report the first academic field experiments manipulating tip request message content, to our knowledge, analyzing 436,969 transactions. We test how three appeals based on tipping motivations—injunctive norms (“It’s customary to leave a tip for the seller’s service”), personalized reciprocity, and impersonal reciprocity—affect tipping and future demand in a global freelance marketplace. On the web, first exposures to the injunctive norms message increased new buyers’ tipping rate by 11.8 percentage points (p.p.) and repeat buyers’ tipping rate by 6.8 p.p. In the app, first exposures to the injunctive norms message increased tipping rate by 2.5 p.p. for new buyers and 1.4 p.p. for repeat buyers. Treatment effects on tipping increase with transaction order price. The norms and personalized reciprocity messages increased subsequent orders and spending in the web experiment and did not significantly change repatronage in the app experiment, suggesting that effective tipping prompts need not reduce future business. Overall, tip request messages can motivate customer tipping to better incentivize and compensate gig workers, but optimization requires careful testing.

History: Hema Yoganarasimhan served as the senior editor.

Supplemental Material: The online appendix is available at https://doi.org/10.1287/mksc.2025.0392.