Forming an implementation intention — "if situation Y, then I will do X" — produced a medium-to-large effect on goal attainment, d = 0.65. It helped people start, protected the intention from distraction, and helped them disengage from plans that were failing.
How it was done
A meta-analysis of 94 independent tests covering more than 8,000 participants, comparing goal intentions against goal intentions plus a specific if-then plan.
What it means
The mechanism is that a concrete cue does the remembering for you. "Message Sara" has to be retrieved by an act of will at some unspecified future moment. "On the bus home tonight, ask Sara how her mum’s surgery went" is triggered by the bus.
This is the best-evidenced lever available for changing whether an intention becomes an action, and it costs nothing to apply — it is a change in how a sentence is written.
It is why a reminder that names a time, a place and a specific thing to say outperforms one that names a person and a number of days.
