September is the real new year. The notebook is new, the plan is fresh, and the resolutions come in a wave: eat better, move more, read the pile of books, finally use the app. A few weeks later most of it is gone. We do this every year, and every year the intention outlasts the action by about three weeks.
This is not a quirk of September. It is the clearest yearly demo of a problem that sits under every study: what people say they will do and what they actually do are two different things. Researchers call it the intention-behavior gap.
The September surge
There is a reason resolutions cluster at certain moments. Hengchen Dai, Katherine Milkman and Jason Riis called it the fresh start effect. A temporal landmark, the start of a week, a month, a birthday, or the back-to-school season, draws a mental line between the old you and a new one, and pushes people toward aspirational behaviour.
The effect is measurable. In their data, people were 33% more likely to go to the gym at the start of a week and 47% more likely at the start of a new semester. The date does not even have to be special in itself. “The first day of spring” motivated more than “the third Thursday of March”, the same day, because people are drawn to beginnings.
September is one of the strongest landmarks of the year, which is why the surge feels so real.
The collapse
The surge does not last. Resolutions fall off fast: a large share are abandoned within the first month, and in fitness the pattern is well known, with a majority of new gym members going inactive within a few months of signing up. The intention was genuine. The follow-through was not there.
The intention was genuine. The follow-through was not there.
Why intentions don’t survive
Paul Sheeran and Thomas Webb reviewed decades of evidence on this in “The Intention-Behavior Gap”. Their conclusion is blunt: intentions explain only a modest part of what people actually do. Changing someone’s intention does not reliably change their behaviour.
The gap is driven by a specific group. Most people who fail to act did intend to act, the “inclined abstainers”. They are not lying and they have not changed their minds. What stops them is the ordinary stuff between intention and action: competing habits, short-term temptations, low willpower in the moment, and no concrete plan for when and how. Information and good intentions are not enough on their own. Without planning and a way past the friction, the intention stays an intention.
What this means for your studies
When a respondent tells you they will buy the product, switch provider, cook from scratch or cut back, you are measuring intent, not behaviour. At a fresh-start moment, that intent is inflated, because the person is picturing their aspirational self, not their Tuesday-evening self.
Ask about the friction, not only the plan. “What would get in the way?” and “the last time you tried, what happened?” surface the inclined-abstainer pattern that a simple intention question hides.
Anchor questions in real, recent behaviour rather than future promises. What someone did last week predicts next week better than what they say they will do.
Watch the timing. An intention captured right after a landmark reads high and fades. If you can, measure the same people again once the fresh-start glow has worn off.
None of this makes stated intent useless. It makes it one signal among several, and usually the most optimistic one. The work is to read it next to what people actually did, and to weigh the friction they will meet on the way.
For how we design interviews to measure past stated intent, see How Verso gets past what people say.
Frequently asked questions
What is the fresh start effect?
The fresh start effect, identified by Dai, Milkman and Riis (2014), is the tendency to pursue goals more strongly right after a temporal landmark such as a new week, month, year, birthday or the back-to-school season. The landmark separates past failures from a “new” self and motivates aspirational behaviour.
What is the intention-behavior gap?
The intention-behavior gap is the gap between what people intend to do and what they actually do. Sheeran and Webb (2016) found that intentions predict only a modest share of behaviour, and that changing intentions does not reliably change behaviour.
Who are “inclined abstainers”?
Inclined abstainers are people who intend to act but do not follow through. They are the main source of the intention-behavior gap. They have not changed their minds; they are stopped by habits, temptations, low willpower in the moment, and the absence of a concrete plan.
Why do September and January resolutions fail so often?
They fail because the intention is formed at a motivational high (a fresh-start moment) but the follow-through depends on planning and friction that the high does not fix. The surge is real, the conditions for lasting change are usually missing.
What does this mean for survey and research design?
Treat stated intent as an optimistic signal, not a prediction. Ask about friction and recent behaviour, not only future plans, and, where possible, measure the same people again after the fresh-start moment has passed.