Implementation Intentions: The If-Then Plan That Makes Habits Stick

An implementation intention is a specific if-then plan that links a situation to an action: "If (or when) situation X happens, then I will do Y." Psychologist Peter Gollwitzer showed that people who plan this way follow through more often than people who only set a goal.

If you've promised yourself to start "tomorrow" more than once, the missing piece is often not the wanting. You never decided when and where.

Below: the formula, the research, 25 examples, habit stacking and WOOP compared, mistakes and a printable planner.

What is an implementation intention?

An implementation intention is a specific if-then plan that links a situation to an action: "If (or when) situation X happens, then I will do Y." It's also called an if-then plan or a when-then plan.

The idea comes from Peter Gollwitzer, a psychologist at NYU and the University of Konstanz. He separated goal intentions from implementation intentions in a 1993 chapter, then made the term famous with a 1999 paper in American Psychologist, "Implementation intentions: Strong effects of simple plans."

It targets the intention-behavior gap. In a 2002 review pooling 10 meta-analyses of 422 studies, Paschal Sheeran found that intentions explained only about 28 percent of the differences in what people actually did. In health behaviors, many people with good intentions never acted on them.

Goal intention vs implementation intention

A goal intention says what you want: "I want to read more." An implementation intention adds when, where and how: "When I get into bed, I will read 10 pages." It builds on the goal; it doesn't replace it.

The if-then formula (and how to write your own plan in 4 steps)

The implementation intention formula is one sentence:

"If (or when) [situation], then I will [action]."

A longer version, "I will [behavior] at [time] in [location]," is the same logic, with a time and a place as the situation.

1. Pick one goal you actually want

   A plan helps you act on a goal, not want it. Choose one you already care about, like reading before bed.

2. Choose a cue you'll meet and notice

   The cue is the "if" part: a moment that shows up on every day you want to act and that you can't miss. It can be a time ("At 7:00 AM"), a place ("When I walk into the gym"), a habit you just did ("After I pour my coffee") or an obstacle ("If I feel too tired to run").

3. Make the action concrete and small

   The "then" part should be something you can start right there. "Read 10 pages" beats "read more." The BJ Fogg Behavior Model (B=MAP) calls this ability: the easier the action, the less motivation it needs.

4. Write it down and rehearse it

   Write the full sentence, then say it out loud or picture yourself doing it in that situation. In the 2024 meta-analysis covered below, rehearsed plans worked better.

Which cue works best?

There's no single winner. In a 2021 trial with 192 adults, Jan Keller and colleagues found that tying a nutrition habit to a daily routine or to a set time worked about equally well. Use a time cue for days with a fixed schedule and a previous action for days that vary; the second is habit stacking, compared below.

If or when? In practice they mean the same. "When" sounds natural for things that happen every day; "if" fits obstacles that may or may not show up.

A good cue passes four checks:

• Specific. "When I close my laptop," not "in the evening."
• Frequent. It happens on every day you want to act.
• Reliable. It doesn't depend on your mood or the weather.
• Noticeable. You can't walk past it without seeing it.

Why if-then plans work

If-then plans work because they move the decision away from the moment itself, to an earlier and calmer one. Gollwitzer's research points to two things, and a third follows from them.

You spot the moment. Planning makes the situation stand out in your mind, so the cue is harder to miss.

The action starts with less thought. Gollwitzer described this in 1993 as "passing the control of one's behavior on to the environment," and his 1999 paper goes further: implementation intentions "create instant habits." When the cue comes, you don't have to choose.

The choice was made earlier. Our take: you decide on a calm Sunday afternoon, not at 10 PM on the couch, when every excuse sounds reasonable.

Compare the two paths. With a goal only, the situation arrives, you decide, and you often skip. With an if-then plan, the situation arrives and you act.

A plan is a shortcut, not the finish line. Repeat the same action after the same cue and it slowly becomes a habit, the process our guide to habit formation walks through.

What the research really shows (and where it falls short)

The exercise study everyone quotes

In a 2002 study of 248 people, Sarah Milne, Sheina Orbell and Paschal Sheeran compared controls, a group that got motivational material about heart disease, and a group that got the same material plus a plan to write: when and where they'd exercise for 20 minutes in the next week.

Of the planners, 91 percent exercised, against fewer than 4 in 10 in each other group. Motivation alone didn't significantly raise exercise. The catch: the outcome was exercising at least once that week, not a lasting habit.

In plain terms, that's a solid difference, not the "twice as likely" some headlines claim. A 2024 meta-analysis of 642 tests by Sheeran, Olivia Listrom and Gollwitzer found average effects from d = 0.27 to 0.66 across thoughts, feelings and behavior, larger when plans were in if-then form, people were highly motivated and they rehearsed the plan.

One caution of our own: positive results get published more often, so read these averages as a best case.

Real-world results

In a 2011 flu shot experiment, Katherine Milkman and colleagues had employees write down a date and time for their shot: vaccination rose 4.2 percentage points above the control group's 33.1 percent. In a field experiment with 287,228 people during the 2008 presidential election, David Nickerson and Todd Rogers found that a voting-plan call raised turnout by 4.1 percentage points among those reached (9.1 in single-voter households). Small per person, big at scale.

Where it falls short

In a 2018 experiment with 877 gym members, Mariana Carrera and colleagues had people make a single plan for their gym visits over the next two weeks; attendance didn't rise. Amy Dalton and Stephen Spiller found that planning's benefit doesn't typically extend to multiple goals. And a plan is not yet a habit: in a 2010 study of 96 volunteers, Phillippa Lally and colleagues found that a daily behavior took a median of 66 days to feel automatic, with estimates from 18 to 254 days.

25 implementation intention examples you can copy

Here are 25 implementation intention examples for everyday goals, from mornings to money, with seven obstacle plans at the end. Each names a cue you can point to and an action you can start on the spot. Pick one, not five, and swap in your own cue.

A vague plan, rewritten. "I'll exercise more" names no moment and no action. "When I get home from work on Monday, Wednesday and Friday, I will change into my running clothes before I sit down" has a time, a place and a first step that takes two minutes.

An obstacle plan for screen time. "If I catch myself scrolling after 9 PM" names the slip itself instead of a clock time, and moving the phone to the hallway puts a few steps between you and the next scroll. You don't have to win the urge, only notice it.

Make a row your own. Keep the shape and swap the details. No train? "When I sit down on the bus" works the same way. The cue only has to be a moment you already meet.

For the focus example, a Pomodoro timer runs the 25 minutes and the break after them.

Implementation intentions vs habit stacking, goals and WOOP

These methods overlap, and most sources blur them together. All of them start from a goal; they differ in what sets off the action and when you'd pick each one.

Habit stacking is a special form of implementation intention: the cue is a habit you already have, in the formula "After I [current habit], I will [new habit]." James Clear frames it this way in Atomic Habits, and our habit stacking guide with 40 examples covers it in full. Our suggestion: use it when your days don't run on a clock.

WOOP comes from psychologist Gabriele Oettingen, who describes it in her 2014 book Rethinking Positive Thinking. You name a wish, picture the best outcome, then find the main obstacle inside you; that pairing of dream and obstacle is called mental contrasting. Only then do you make a plan, in the form "If [obstacle], then I will [action]." It helps most when the thing in your way is you: tiredness, doubt, the urge to put it off.

A coping plan is that last step on its own: an if-then plan for an obstacle you already know, like rain on a running day or a late meeting on a gym night. Add one to any plan above, so a bad day bends the plan instead of breaking it.

Which to choose? WOOP when you keep getting in your own way; for everything else, a plain if-then plan with a time or habit cue does the job.

7 mistakes that make if-then plans fail

When a plan fails, it's usually one of these.

1. The cue is vague. "In the evening" is hours long, not a moment. Fix: name an action or a clock time, like "when I close my laptop."

2. The cue is rare or easy to miss. A cue you meet twice a month can't carry a daily habit. Fix: pick one you meet every day, where you'll see it.

3. The action is too big. "Then I will work out for an hour" collapses on a tired Tuesday. Fix (our rule of thumb): make the first step something you can start in under 2 minutes.

4. Too many plans at once. As Dalton and Spiller found, the benefit fades across many goals. Fix: one plan, two at most; add the next once the first runs.

5. The plan only forbids. In studies on unhealthy eating habits, Marieke Adriaanse and colleagues found that "if X, then not Y" plans could ironically strengthen the habit they targeted, unlike replacement plans. Fix: plan what you'll do instead, like the swaps in our bad habits examples, each with a replacement.

6. No plan for the obstacle you know. The rain, the late meeting and the 9 PM slump will come. Fix: add one coping plan, "If [obstacle], then I will [smaller action]."

7. The goal isn't really yours. The 2024 meta-analysis found bigger effects in highly motivated people. Fix: before you plan, finish the sentence "I want this because ___." If you can't, pick a different goal.

Check your plan:

• The cue is specific: I can point to it.
• It happens on every day I want to act.
• I can start the action in under 2 minutes.
• It's my only new plan right now, or one of two.
• It says what I'll do, not only what I won't.

How to turn your if-then plans into a daily routine

Loose plans live on paper or in your head, and that's where they fade. The gym study is the warning: plans made once on a form didn't change attendance. A routine puts your plans at one moment of the day, in the same order every time.

Repetition is what counts. In Keller's trial, carrying out the plan again and again was a key predictor of how automatic it became. Only 23 percent of participants reached the study's threshold for a formed habit within 84 days, and those who did needed a median of 59 days to get there, numbers we unpack in how many days it takes to form a habit.

We built Greatr around this idea. You build a morning routine, an evening routine or both by stacking small habits in a fixed order, then tap Play and run them one habit at a time. Each habit's "when" is the one before it, and the routine itself can be your time cue: "When I get up, I will start my morning routine."

The app also runs one if-then plan for you: the apps you choose, like Instagram or TikTok, stay locked until you finish your routine, and the lock screen says "Finish your routine and these open." Otto, your guide in the app, keeps count of every day you show up.

Our suggestion: pick your best plan from the table above and make it the first habit of your morning routine.

Printable if-then planner

Print this page, or copy the table into a notebook. Fill in your goal, one or two when-then plans and one obstacle plan. Each evening for a week, mark whether you did it.

An example for reading: when I get into bed, I will read 10 pages; if I'm too tired, then I will read one page.

Prefer your phone? Add the plan as a habit in a Greatr routine and let Otto keep count.

Your next step, tonight: write one "When [cue], I will [action]" line for a moment you'll meet tomorrow morning, and put it where that moment happens.