As David Epstein @DavidEpstein recently pointed out in his newsletter, Range Widely, the first of January is a great time to make resolutions.

Behavioural economist Katy Milkman @Katy_Milkman, with Hengchen Dai and Jason Riis, discovered evidence for a “fresh start effect” – people are more likely to take action towards a goal if a landmark date (such as the first day of spring) is made salient.

All very good. But in the spirit of friendly debate, I pointed out to David that making resolutions is not really the problem. The problem is keeping them.

And a lot of behavioural science focuses on measuring quick wins – signing up for a gym membership, rather than training for the 100th time – so we probably have more answers than we want on how to motivate short-term actions, and fewer than we need on long-term stickability.

David and I each agreed to go away and think about it. @Katy_Milkman kindly offered some pointers, too. And although I am still thinking about it (watch this space) the time feels right to reveal what I have learned so far…

Step One: Make a plan. Let’s say your resolution is “get in shape in 2022”. Fine. But how, exactly? Be specific. If you’re planning to start running, when? Consider committing to specific regular actions – say, a weekly exercise class rather than a generic gym membership.

“Beyond Good Intentions“, a paper from Rogers, Milkman, John and Norton, finds that people are more likely to follow through on aspirations if they’ve been prompted to make a specific action plan.

Step Two: Don’t just step on the accelerator, release the handbrake. (This idea from Kurt Lewin, via Daniel Kahneman.) Let’s say your resolution is to read more books. Ask yourself why you aren’t already reading more books. What’s been getting in the way? Can you make a specific plan to remove the obstacles?

Step Three: Make only one resolution. The idea of “keystone habits”, popularised in Charles Duhigg’s book The Power of Habit, suggests that one good habit can lead to others. This is a plausible idea, but it’s probably best to start with the one good habit and shelve the others for now.

I find this difficult. I love making lists and typically at New Year I have half a dozen things I’d like to achieve or improve. But this year I’m going to start with just one. The list isn’t going anywhere – there’s always the 1st of February and the 1st of March, after all.

Step Four: If you’re trying to eliminate a bad habit, try to replace it with a good one. Duhigg argues that it’s far easier to modify a habit than eliminate it. Use the old trigger and perhaps the old reward, but substitute a new behaviour.

For example, let’s say you want to quit Facebook. Identify when you tend to reflexively check Facebook, and figure out what you’re going to do instead. Maybe you want to read a trashy novel. Keep it on your desk – or maybe beside the lavatory. Or maybe the plan is to try to call old friends, and every time you feel the itch to check Facebook, make the phone call instead.

To summarise: make a specific plan, identify obstacles to keeping your resolution, make only one resolution at a time, and find positive activities to substitute for bad habits.

There’s more to say, but I’ll say it another time. I recommend Duhigg’s book, and Katy Milkman’s How To Change has become the bible on this topic. Also look out for a new book from Ayelet Fishbach, Get It Done.