From chapter 1, The Llama Pace

A plan with a hinge

This note is from Running with Llamas. It is general education, not care. The chapter rates the practice moderate.

A vague goal is easy to postpone, because it never says what to do when the kettle boils. An implementation intention is a plan with a hinge: if this situation happens, then I will do that. The situation is one the day already contains. The action is small enough that the sentence is still true when you are tired.

A 2006 meta-analysis found a medium-to-large average effect on goal achievement. The result was d = 0.65, from 94 tests and 8,461 participants (95 percent confidence interval 0.60 to 0.70). Medium-to-large is a description of that average. It is not a promise about a percentage of your life. People who spelled out when and where they would act were, on average, more likely to follow through than people who only held the goal.

If the action is enormous, the sentence becomes fiction. "After I pour coffee, I will put on my walking shoes" can survive a hard morning. "After I pour coffee, I will run ten kilometers" often will not. The plan can be about the shoes. The walk is allowed to grow later.

Repetition is what turns the sentence into a habit. Twenty-one days is the number that escaped into the culture. The studies do not support it. In one modest study, 96 volunteers took part, 82 had enough data, the model fit 62, and the fit was good for 39. Among those 39, the median time to 95 percent of their automaticity plateau was 66 days, and the range ran from 18 to 254. Missing one opportunity did not materially undo the process. A 2024 review of 20 studies and 2,601 participants found only a handful of studies that actually timed a habit. They did not agree with one another, and they did not agree with twenty-one days.

Otis, the llama in the book, says, "Slow is not the opposite of progress. Stopping is."