Fewer sign-ups, more use Carpool platform study, Oregon DOT (N=27,227) — indexed to the low-effort group = 100 0 50 100 150 175 100 100 Low-effort sign-up (one click) 75 160 High-effort sign-up (re-enter commute details) Share who registered Carpool trips per registered user, per week Source: Dykstra, O’Flaherty & Whillans, “The Buy-In Effect,” Management Science (forthcoming); Harvard Business School Working Knowledge.
A second study, run separately with an unrelated online task, found the same shape of result. People who completed a 15-question survey before starting were 37% more likely to return for a second day than people who signed up in one click, and finished about half again as much work. The researchers describe this as the “buy-in effect”: a small, relevant amount of effort at the outset appears to build ownership over a behavior in a way a frictionless click does not.
Two experiments, one pattern A harder sign-up reduced enrollment but increased follow-through, in a real commute and an online task Study 1 — Carpool platform Oregon Department of Transportation, 27,227 users -25% fewer sign-ups with the harder registration 1.6× more carpool trips per week, per registered user +795 more total carpool trips over four months, despite fewer people enrolled Study 2 — Online task work Transcription task, two-day return window +37% more likely to return for a second day +51% more work completed by the high-effort group High-effort sign-up: 15-question survey Low-effort sign-up: single click 8,438 vs. 5,598 letters transcribed, high- vs. low-effort group Same pattern, two very different behaviors — a sign of a real effect, not a fluke of one setting Source: Dykstra, O’Flaherty & Whillans, “The Buy-In Effect,” Management Science (forthcoming); Harvard Business School Working Knowledge.
