Framework · Behavioral science · Actionable Gamification
Endowed progress effect
People persist more when a task looks already started. In the original car-wash field study, completion was 19% for a blank 8-stamp card versus 34% for a 10-stamp card with 2 stamps given. Credit only genuine actions. Moderate evidence (B), with few direct replications.
Plain label: credit real progress already madeAlso known as: endowed progress, head start, checklist pre-fill
Core idea. Persistence follows relative progress, not the value of what would be lost. F10 (The endowed progress effect: how artificial advancement increases effort, Nunes & Dreze, Journal of Consumer Research, 2006)
Evidence. One field experiment plus four studies in the same paper Evidence grade B. Moderate evidence: solid studies with some limits.. Few independent direct replications exist, so treat the lift as illustrative ("in the original study"). Some blogs misreport it as 82%; the reported numbers are 19% vs 34%.
How it plugs in. "Account created, email verified: 2 of 6 steps done." Start a new user's checklist partly complete by counting real actions, and import data at sign-up so the space isn't empty: real progress plus a sense of ownership. HK-ACT32 (Hooked Ch.3)
Watch-outs. Crediting actions the user never took is fake progress and destroys trust in the bar.
Limits
What we don’t claim
- The Hook Model is a practical design tool, not a validated or complete theory of behavior.Hooked, Introduction
- Octalysis is a practitioner framework built from observing games, not a validated scientific model.Actionable Gamification Ch.15, pp.399-400
Sources
Actionable Gamification · Yu-kai Chou
Ch.6, p.111
Hooked · Nir Eyal
Ch.3
The endowed progress effect: how artificial advancement increases effort · Nunes and Dreze, Journal of Consumer Research 32(4), 2006
Evidence grade B. Moderate evidence: solid studies with some limits.The endowed progress effect: how artificial advancement increases effort · Nunes & Dreze, Journal of Consumer Research, 2006
Evidence grade B. Moderate evidence: solid studies with some limits.
Book content is paraphrased, never quoted at length. Last verified October 24, 2026.
Your product
Find the stage your product is stuck in
Gamify It reads your product, picks the one move that matters at its stage, and sizes the test to your traffic. Connecting is free; a Pro subscription starts it.