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Title: The effectiveness of commitment devices : field experiments on health behaviour change
Author: Savani, M. M.
ISNI:       0000 0004 7224 5066
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2017
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Behavioural public policy, as popularised by the “nudge” agenda, aims to help people make better choices in the face of their inherent biases (Thaler and Sunstein, 2008), including over diet and weight management (Liu et al, 2014). Present bias can lead to time inconsistency: individuals identify an optimal course of action but when the moment comes to take that action they delay or quit, prioritizing present gains at the expense of longer term benefits (O’ Donoghue and Rabin, 1999). Time inconsistency is explained in Thaler and Shefrin’s dual-self model (1981) as the result of an internal tussle between a myopic ‘doer’ and a far-sighted ‘planner’. Commitment devices – voluntary strategies to change future behaviours – can help people stay on track with their goals. Emerging empirical evidence from psychology, medicine, and behavioural economics bears out this prediction for health behaviours (Prestwich et al, 2012; Volpp et al, 2008; Giné et al, 2010), but commitment devices remain relatively under-researched (Perry et al, 2015). The dissertation sets out a fresh analytical framework applying, for the first time, planner-doer theory to health behaviours for weight loss. It also explores how commitment devices might work differently across sub-groups. The empirical strategy, combining quantitative and qualitative methods, centres on two field experiments testing for average and heterogeneous treatment effects of commitment devices on self-monitoring behaviour, participation in a weight loss programme, and weight loss outcomes. Results indicate commitment devices improve health behaviours, but have mixed effects on weight loss: highlighting the potential for commitment overload, and the importance of choosing the right dose of commitment. Qualitative evidence provides fresh insights for planner-doer theory. Differential impacts on sub-groups imply a need for careful targeting and design of commitment devices. The dissertation concludes there is scope for commitment devices to play an effective role in behaviour change programmes.
Supervisor: John, P. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available