Goal gradient
Also said as Goal-gradient hypothesis, Speeding up near the end
Effort rises as you get closer to a goal. Clark Hull proposed it in 1932 and tested it with rats in a runway, which ran faster the nearer they were to food.
It tells you that the middle of a long bar is where people drop off, so break big goals into smaller ones. Ran Kivetz, Oleg Urminsky and Yuhuang Zheng revived it in 2006: café customers shortened the time between coffees by about 20% between the first stamp and the last, and customers on a 12-stamp card with 2 free finished ten purchases in 12.7 days against 15.6.
Say it
“The 100-level pass loses people around level 40. Split it into ten chapters of ten levels with a reward at the end of each, so nobody is ever more than ten levels from a finish.”
Where you’ve seen it
World of Warcraft's experience bar is split into 20 visible bubbles, so there is always a small goal nearby, and people play on to reach the next one.
Not to be confused with endowed progress effect
A goal gradient is the speeding up on the way. The endowed progress effect is the head start at the beginning.