Goal Gradient Effect

What it is

The effect describes a relationship between perceived distance and effort. The nearer a goal appears, the more effort people put in per step. Kivetz and colleagues tested it in three settings. In a café loyalty programme, across nearly a thousand completed cards, the time between purchases shrank by about a fifth as customers approached their reward. In a music-rating website, members rated songs faster as they neared a voucher. And in an experiment with 108 café customers, those given a 12-stamp card with 2 bonus stamps completed their 10 required purchases in 12.7 days on average, against 15.6 days for customers with a plain 10-stamp card.

That last result matters because the extra stamps did not change the work required. The customers had the same ten purchases to make, but the card made them look further along, and they sped up. Progress that was given rather than earned still pulled them forward.

In effect

The goal gradient is the mechanism behind many loyalty cards, progress bars and completion trackers. It is also the reason a head start can help: Joseph Nunes and Xavier Drèze's 2006 car wash study found that customers given a card with two stamps already filled were more likely to finish it than customers with a blank card needing the same number of washes.

Kivetz and colleagues also found that customers who sped up more on their first card were likelier to earn a second reward and came back sooner. After a reward, though, the purchase rate reset, so the effect drives effort towards a goal rather than loyalty in general.

What it does not say

The goal gradient does not say that motivation rises evenly from start to finish. Andrea Bonezzi and colleagues found in 2011 that motivation can be high near the start and near the end, and lower in the middle, depending on whether people measure progress from where they began or from where they are heading. Ana Villar's 2013 meta-analysis of progress indicators in online surveys found that a bar moving fast at first and slowly later reduced abandonment, while one moving slowly at first increased it. Showing progress helps only when what it shows encourages people.

Nor does it say that a head start always works. Ying Zhang and Szu-chi Huang found in 2010 that the same progress can raise or lower commitment depending on whether people credit it to themselves and on the stage of the goal.

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