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Too much of a good thing? Personal accountability and commitment to health goals

By Emma Norris, on 5 March 2019

By Manu Savani – University College London, UK

Like me, you might be thinking about how to be healthier and happier in the year ahead. Health behaviours often involve a trade-off – we pay the price now for making the change, but the benefits may only be felt further down the road. For example, we take up a new diet or gym class; it feels like hard work now but gives us hope that we will fit back into the t-shirt and shorts in the summer. Every time we make decisions that affect our health goals, such as selecting from a menu or reaching for the running shoes, we have to choose between listening to our forward-looking ‘planner’ self and our myopic ‘doer’ self.  Faced with such a choice, we might be tempted to privilege current gains over future gains, a phenomenon familiar to us as ‘present bias’. So how do we stay on track with our goals?

Commitment devices might help – personal strategies that bind your future self to desired behaviours  – and are increasingly a feature of weight loss toolkits. Deposit contracts set aside a sum of money that will be lost unless a goal is achieved. The idea is to create a cost, felt by the present-biased ‘doer’ self, which aligns current actions with future goals. Another way to do this is by creating a reputational cost through a public pledge to achieve a goal.

In my new study, I set out to test the effect of a reputational commitment device on health goals, with a field experiment involving users of an online weight loss service.

Clients had access to calorie counting tools and paid around £5 monthly membership fees for the service. 118 participants randomly assigned to a reputational commitment intervention were invited to name a weight loss coach, a supportive friend or family member who was aware of the weight loss target and might be asked to verify progress after four weeks. Planner-doer theory implies that making the weight loss target known to others would increase accountability to that target by generating a psychological tax to reneging. Digital health scholars suggest human support can enhance the effectiveness of such online interventions. Participants offered the added reputational commitment were therefore expected to report higher weight loss than the comparison group (n=145), who continued with the normal service, paying their fee but with no extra commitment strategies.

Data on weight loss at twelve weeks showed that on average both experimental groups lost weight, with the reputational intervention group self-reporting 1.1% average weight loss compared to 2.2% in the comparison group.

The reputational commitment strategy did not work as expected, and my analysis explores possible reasons for this unexpected finding. Participants who named a coach may have experienced ‘commitment overload’, which might explain why those who complied with the reputational intervention (41% who named a coach) experienced 4.4 kg less weight loss than the comparison group. This explanation is speculative and puzzles remain – for example, it is not clear why the effects become more pronounced at twelve weeks, when the groups demonstrated fairly even weight loss progress at four weeks.  

What we can learn from this research is that reputational commitment devices can have a significant – but unpredictable – impact on health behaviours. For policy designers, it would be wrong to exclude reputational commitment strategies from the menu of weight loss aids. The intervention supported people differently, with some participants losing more than 10% of their initial weight. A quarter of participants who declined to name a coach could not think of someone suitable, suggesting there may be demand for support and accountability on a personal level.

These strategies need to be better understood in order to harness potential positive effects. Future work might explore how to identify the optimal level and type of commitment to motivate behaviour change, and how best to combine online and offline weight loss strategies. In the mean time, you could tell someone about your health goals for the year. But go easy on yourself – one commitment strategy at a time.

Read the paper: “The Effects of a Commitment Device on Health Outcomes: Reputational Commitment and Weight Loss in an Online Experiment”.


  • Have you tried any reputational commitment strategies? If yes, how did you find it? If no, why doesn’t it appeal?
  • Is ‘commitment overload’ or ‘commitment saturation’ a plausible explanation?
  • How might we identify in advance whether people are likely to benefit from additional layers of commitment?


Dr Manu Savani is a Teaching Fellow in Public Policy at UCL Department of Political Science. Her doctoral research in behavioural public policy examined the impact of a variety of commitment devices in health behaviour change, using experimental and qualitative methods. Manu’s current research continues to ask how programmes and policy can be designed to take account of behavioural biases, with a focus on welfare policy and financial decision-making: https://www.ucl.ac.uk/political-science/people/teaching/manu-savani




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