Does the intention-behavior gap shrink with experience?

Only up to a point. Sheeran and Webb (2016) describe an inverted U: early repetitions make an intention more stable and so more predictive of action, but once a behavior turns automatic, intention stops being the thing that drives it and predictive power falls again. The same review reports that socioeconomic status moderates the gap, which is a reminder that some people have far less room to act on a plan than others do.

Are some kinds of goals easier to achieve than others?

The review's summary is that goals framed as moving toward something, goals chosen for your own reasons, and goals about learning rather than performance are more likely to be reached. Concrete goals beat 'do your best' goals (Locke and Latham). Optimism is mixed: students underestimate how long coursework takes (Buehler, Griffin and Ross, 1994), yet Zhang and Fishbach (2010) found that people set ambitious targets put in more effort and did better.

Is low willpower the reason intentions fail?

It contributes, but it is one of five problems rather than the main one. Studies cited in the review found people with weaker executive function on Stroop and Go/No-Go tasks translated intentions into action less often, and the same held for lower conscientiousness. The ego-depletion account of willpower as a tank that empties is contested; the review notes the debate over its size and meaning and does not treat it as settled.

Does telling other people about a goal help or hurt?

The evidence points both ways, depending on what is shared. Gollwitzer, Sheeran, Michalski and Seifert (2009) found that when an intention served an identity goal and other people noticed it, the person felt they already had the identity and acted on the intention less. Harkin et al.'s monitoring meta-analysis found larger effects when progress was physically recorded or made public, so sharing a progress record fares better than announcing an aspiration.

Why Am I Not Achieving My Goals? Five Places the Plan Breaks, According to the Intention-Behavior Research

A 2013 meta-analysis in the British Journal of Health Psychology turned a very ordinary sentence, “I’m going to be more active,” into percentages. Rhodes and de Bruijn pooled 10 studies and 3,899 people. Of everyone followed, 42% intended to be active and were, 36% intended to be active and were not, 21% neither intended nor acted, and 2% acted without having intended to. Among the people who set out to do something, 46% did not do it (the authors’ abstract reports the overall gap as 46% and, in its plain-language summary, 48%).

That is the short answer to why you might not be achieving your goals. For a lot of people the goal exists and the intention is sincere. The failure comes afterward, in a stretch of ordinary days that the intention was never built to survive. Researchers who study this call the people stuck there “inclined abstainers”: they intend to change and do not.

What the intention-behavior gap actually measures

Intentions do predict behavior. Sheeran (2002) pooled 10 earlier meta-analyses covering 422 studies and found a correlation of .53 between intention at one point in time and behavior later. A large correlation tempts you to conclude that strengthening the intention is the lever to pull.

Experiments say otherwise. Webb and Sheeran (2006) gathered 47 trials in which people were randomly assigned to something that raised their intentions and then tracked what they did. A medium-to-large rise in intention (d = 0.66) bought only a small-to-medium rise in behavior (d = 0.36). Wanting it more is a weak lever.

Paschal Sheeran and Thomas Webb’s 2016 review in Social and Personality Psychology Compass, which I read in full as an accepted manuscript, concludes that intentions are translated into action about half the time. Its useful move is to split the journey into getting started, staying on track and finishing, and to list what goes wrong in each. What follows is my arrangement of that list into five stops, ordered by when they bite. It is a reading aid, not a validated test.

Stop 1: the intention was weak or borrowed

Before the first day, the quality of the intention already matters. The review calls temporal stability, meaning whether the intention holds from one week to the next, the best single indicator that an intention will be carried out. Intentions rooted in what a person believes will happen if they act predict behavior better than those rooted in social pressure. Goals framed as approach and goals pursued out of personal interest get reached more often.

Practically, a goal you hold because someone else expects it is the most likely to evaporate. Sheldon and Elliot’s self-concordance study is the cleanest test of that idea, and a four-question version of it is worth running on any goal you have already failed at twice.

Stop 2: the moment to act came and went

Starting problems the review lists include forgetting to act, missing the opportunity and skipping the preparation. Forgetting sounds trivial until you read the numbers. Einstein and colleagues (2003) asked young, healthy volunteers to hold an intention for a few seconds. After 5 seconds, 8% forgot; with attention divided, 24% did (figures as reported in the review; I read only the paper’s abstract). The abstract adds that rehearsal and implementation-intention strategies did not remove the rapid forgetting in two later experiments, a useful reminder that if-then planning is not a cure-all.

Opportunities are missed most when they are brief or infrequent, when a deadline is involved, or when several routes to the goal exist and you have not chosen one. A goal like “get fit” never announces its own start time. Prospective memory, the faculty that carries an intention to its moment, is where this stop plays out.

Stop 3: the moment came and you renegotiated

Often the opportunity is noticed and a competing want wins. Taylor, Webb and Sheeran (2014, British Journal of Social Psychology) asked what people say to themselves at that point. Study 1 found six justifications for indulging: I deserve it, I’m curious, this is an exception, I can make up for it later, it’s available, it’s irresistible. In Study 2, using these justifications undermined strong intentions to halve a high-fat food, but not weak ones. Study 3 found that priming people to use justifications raised how much chocolate they ate afterward. I read the abstract, not the full paper.

The detail that matters is the last one. The people most likely to talk themselves out of it were the ones who cared most. Strong intention gives you more to rationalize around.

Stop 4: you stopped looking at the scoreboard

Progress checking is one of the better-supported fixes. According to the review, Harkin et al. (2016) found that interventions that made people monitor progress far more often (d+ = 1.98) moved behavior by a smaller but real amount (d+ = .40), with bigger effects when progress was written down or shared. The monitoring meta-analysis has the full account.

The catch is that people avoid checking, particularly when they suspect the news is bad. Webb and colleagues named this “the ostrich problem.” In Chang, Webb and Benn’s (2017) two studies, the most strongly endorsed reasons for not monitoring were that progress information would demand a change in beliefs or an unwelcome action, that progress was poor, and that thinking about the goal felt bad. Skipping the scoreboard is a way of protecting your picture of yourself, which is why it feels like nothing at the time.

Stop 5: an older habit or a competing goal took the wheel

The fifth stop is the one effort cannot reach, because you do not notice it happening. The review reports that situational cues can switch on competing goals without awareness. In one study, priming the goal of moving fast undermined intentions to drive safely (Gollwitzer et al., 2011). It also notes that the link between intention and behavior is weaker for habitual behaviors, since a familiar cue produces the action without anyone consulting the intention.

If the thing you keep doing instead of the thing you meant to do is attached to a place or a moment, the repair belongs in the setting. Wood’s diary and university-transfer studies show how much of a habit lives in its surroundings.

The five stops side by side

Stop	What it looks like	Best-supported response
1. Weak or borrowed intention	You can’t say why you want it, or the reason is someone else’s	Rewrite the goal in your own terms, or drop it
2. Moment missed	“I never got round to it”	Name the cue in advance (an if-then plan; pooled effect d+ = 0.65 across 94 studies per Gollwitzer and Sheeran, 2006)
3. Renegotiation	You decide to skip at the moment, with a good reason	Decide the response to your top excuse before it arrives
4. Scoreboard avoided	You haven’t looked in weeks	Record progress where someone else can see it
5. Autopilot	You do the old thing without deciding to	Change the cue or the setting

Finding your stop

Five questions, in order, will usually locate the break:

Could you state, in one sentence and without mentioning another person, why you want this?
Is there a particular moment each day or week at which the first action happens?
At that moment, do you ever decide to skip, with a reason that feels fair?
Can you say right now, with a number, how far along you are?
When you slip, does it feel like a decision or like waking up already doing something else?

Stop 3 is where waking up lives. The decision to get out of bed is taken at the moment of waking by someone whose judgment is at its worst, and the justifications from Taylor’s list (“just five more minutes”, “I’ll make it up tonight”) arrive on schedule. DontSnooze, a free alarm app, aims at that one stop: when the alarm goes off you have 30 seconds to record a video showing you are up, and if you don’t, a random photo from your camera roll is sent to friends you chose in advance, so the cost of renegotiating is set before you are awake enough to haggle.

What this evidence cannot tell you

The Sheeran and Webb review is a narrative synthesis, not a systematic one, and much of what it cites comes from health behaviors and student samples with short follow-ups and self-reported outcomes. The Rhodes and de Bruijn figure covers physical activity only, from 10 studies. “About half” is an average across behaviors, and finances, careers and creative work have not been measured in the same way. The sorting of failures into five stops is mine. I read the Sheeran and Webb manuscript in full and only the abstracts of Webb and Sheeran (2006), Rhodes and de Bruijn (2013), Einstein et al. (2003), Taylor et al. (2014) and Chang et al. (2017); the effect sizes attributed to Harkin, Gollwitzer and Sheeran, and Gollwitzer et al. (2011) come from the review’s account.

If the honest answer is that everything is stalling at once, a 48-hour order of operations is a gentler place to start than a new goal.

So the cheapest next move is to find the earliest stop that fits. A fix at stop 4 does nothing for a goal that dies at stop 1, which is why the five questions run in the order a goal travels: the first one you answer badly is the place to start.