Two studies started the modern interest in defaults. What they found is subtler than the headline.

Organ donors and retirement savers

In 2003 Eric Johnson and Daniel Goldstein asked 161 people online whether they would be organ donors. The only thing that changed between groups was the default. When people had to opt in, 42% agreed. When they had to opt out, 82% stayed in. With no default at all, forced to choose, 79% agreed Published. Across European countries the gap was the same shape and bigger: effective consent of 12% in Germany, where people opt in, against 99.98% in Austria, where they opt out Published.

Two years earlier, Brigitte Madrian and Dennis Shea had looked at a large US employer that switched its 401(k) from opt-in to automatic enrollment. Among employees with similar tenure, participation was 37% before the switch and 86% after Published. Only the default changed.

Same choice, different box ticked

Share who ended up in, by which answer was preselected

Had to opt inHad to opt out

Organ donor consentOnline experiment, 2003

42%

82%

401(k) participationOne employer, before and after

37%

86%

PublishedJohnson and Goldstein, Science, 2003; Madrian and Shea, Quarterly Journal of Economics, 2001.

The part that gets left out

Both studies carry a warning the famous chart hides. Six in ten automatically enrolled employees did nothing to change the company’s choice of a 3% contribution in a money market fund, and 80% of their contributions went to that fund Published. The default raised participation and anchored people at a savings rate few had chosen. The authors put it down to inertia and to employees reading the default as advice.

And consent is not donation. Johnson and Goldstein estimated that an opt-out default was associated with a 16.3% rise in actual donation rates, from 14.1 to 16.4 donors per million Published. A real gain, far smaller than a 60-point gap in consent. Between the box and the outcome sat families, doctors and practical steps.

A default moves the box. What happens after the box is still up to the customer.

That’s the first lesson for a store. A preselected box moves take-up. Whether it moves reorders, margin or a list that buys depends on what happens next, which is where bad defaults fail.

Three reasons defaults work

A meta-analysis of 58 default studies by Jon Jachimowicz and colleagues tested three explanations Published:

• Effort. Changing the answer takes a click, and some people won’t spend it. Surprisingly, this didn’t explain which defaults were stronger.
• Endorsement. People read the preselected option as what the seller recommends. Defaults that work this way were more effective.
• Endowment. The preselected option feels like what you already have, so giving it up feels like a loss. These were more effective too.

Endorsement matters most for a brand. Preselect subscribe-and-save and the customer reads it as advice. If the advice is good, the default is a service. If not, you’ve spent credibility, and the customer finds out at the first renewal.

It works on price, too

In a German experiment with online energy orders, making the pricier green tariff the default increased its purchase nearly tenfold Published. In 13 million New York taxi rides, suggested tips moved what riders tipped, but higher suggestions pushed more riders to leave no card tip at all Published. Push a default too far and some people opt out of the whole thing.

Do this

• Add a column to your list of preselected choices: “What the default tells the customer we recommend.” If you wouldn’t say it out loud to a customer on the phone, the default is wrong.