Easy sign-ups can quietly kill follow-through.

In a field experiment with 27 227 inactive users of Oregon’s carpool platform, half could move their account to a new site in one click. The other half had to re-enter their information. A quarter fewer of them made the move, yet that group as a whole took 1.6 times as many carpool trips per week.

Fewer people joined. The ones who did used it far more.

A little friction cut sign-ups by a quarter

Holly Dykstra of the University of Konstanz, Shibeal O’Flaherty of the US Office of Evaluation Sciences and Ashley Whillans of Harvard Business School ran two randomized experiments. Their paper was published in Management Science, a leading peer-reviewed management journal.

In 2019, the Oregon Department of Transportation moved its carpool-matching website to a new platform. Inactive users had to move their accounts over, and the researchers randomly split 27 227 of them:

  • Low effort: move the account with one click.
  • High effort: move the account by re-entering their information.

They then tracked carpool trips for four months.

The effortful process led to 25% fewer people moving their accounts. That’s a quarter of potential users lost at the door.

The harder group took 1.6 times as many carpool trips

Count everyone invited, including people who never signed up, and the high-effort group still carpooled far more.

  • 1.6 times as many carpool trips per week.
  • About 795 extra trips over four months.

Losing a quarter of sign-ups didn’t hurt, because the people who joined used the platform much more.

Fewer sign-ups, more real use.

The same thing happened with a deliberately boring job

In a second study, online workers transcribed rows of 35 blurry Greek letters, a tedious task by design, and could choose whether to come back for a second session. Before starting, they signed up either with one click or by answering a 15-question survey relevant to the task.

  • 37% more likely to return for a second session after the effortful sign-up.
  • More work completed overall.

Effort changed behaviour, not just who joined

The obvious explanation is filtering: the extra step weeds out the least committed. The authors found that this explains only part of the effect.

Something about making the effort itself seemed to change what people did.

Their suggestion: investing effort makes an activity feel more valuable and builds a sense of ownership. It becomes “my” commitment, not something you clicked through. That echoes the IKEA effect, where people value furniture they assembled themselves more than identical ready-made furniture.

A gym membership bought on a whim is easy to forget. One where you planned your days, and why, feels like a promise to yourself.

Only relevant effort helps, and only for follow-through

The kind of effort matters. Re-entering your details or answering questions about the task makes you think, briefly, about what you’re signing up for. Pointless hoops, like a slow website or an irrelevant form, are just annoying.

According to the researchers, the buy-in effect is most likely when:

  • Follow-through is the goal, not just enrolment.
  • Both the sign-up and the behaviour are voluntary.
  • The effort is modest and relevant to the goal.

Don’t add friction where access is the real problem. For set-and-forget decisions like retirement saving, automatic enrolment works because nothing more is needed after signing up. Extra effort there just means fewer people saving.

Judge your programme by use, not headcount

If you run a wellness scheme, a mentoring network or a training course, consider one short, meaningful step at sign-up: a few questions about goals, a brief planning call, or choosing preferences. Expect fewer sign-ups.

For your own habits, a reasonable inference, not something the studies tested, is that a small upfront investment helps too:

  • Write down why you’re starting and what you want from it.
  • Plan the specifics: when, where and how.
  • Do the setup properly, such as preparing your kit or booking the sessions.

What the study can’t tell you

  • Fewer people join. If reach matters more than follow-through, friction is the wrong tool.
  • Too much effort could backfire. The studies tested modest, relevant steps, not long or arbitrary ones.
  • These were two specific settings: inactive carpool users in Oregon and an online transcription task.
  • The time frames were short: four months of carpooling, and one return session online.
  • The personal-habit advice is untested. The studies looked at sign-up processes, not people designing their own commitments.

Stop judging success by sign-ups

A bigger number at the door can mean less real use.

Before you remove the next step from a sign-up, ask whether it’s the step that makes people commit.