The causal link between financial incentives and weight loss: an evidence‐based survey of the literature

TLDR: In this paper, the authors review the available evidence, properly emphasizing studies that credibly yield meaningful estimates of the effect of financial incentives on weight loss and find that the scientific literature on the subject has not yet satisfactorily settled whether such a mechanism is effective at eliciting the desired behavioral and health outcomes.

Abstract: Obesity and overweight are linked to diseases that cost society a significant amount of resources. While behavior modification can reduce the problem, instigating such lifestyle changes is an uneasy task. One potential way to reduce the problem is through the use of financial incentives. In this survey, we review the available evidence, properly emphasizing studies that credibly yield meaningful estimates of the effect of financial incentives on weight loss. We find that the scientific literature on the subject has not yet satisfactorily settled whether such a mechanism is effective at eliciting the desired behavioral and health outcomes. We therefore advocate a rigorous large-scale randomized experiment to provide reliable estimates of the effect.

Figures

TABLE 3 A taxonomy for studies on the link between financial incentives and obesity and overweight

TABLE 1 Percentage share of adult population with a BMI greater than 30 kg/m2

TABLE 5 Study design of Jeffery et al. (1993b)

TABLE 6 Study design of Saccone and Israel (1978)

TABLE 2 Hypothetical study designs

TABLE 4 Study design of Finkelstein et al. (2007)

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RUHR
ECONOMIC PAPERS
The Causal Link Between
Financial Incentives and Weight Loss
An Evidence-based Survey of the Literature
#290
Alfredo R. Paloyo
Arndt Rüdiger Reichert
Holger Reinermann
Harald Tauchmann

Imprint
Ruhr Economic Papers
Published by
Ruhr-Universität Bochum (RUB), Department of Economics
Universitätsstr. 150, 44801 Bochum, Germany
Technische Universität Dortmund, Department of Economic and Social Sciences
Vogelpothsweg 87, 44227 Dortmund, Germany
Universität Duisburg-Essen, Department of Economics
Universitätsstr. 12, 45117 Essen, Germany
Rheinisch-Westfälisches Institut für Wirtschaftsforschung (RWI)
Hohenzollernstr. 1-3, 45128 Essen, Germany
Editors
Prof. Dr. Thomas K. Bauer
RUB, Department of Economics, Empirical Economics
Phone: +49 (0) 234/3 22 83 41, e-mail: thomas.bauer@rub.de
Prof. Dr. Wolfgang Leininger
Technische Universität Dortmund, Department of Economic and Social Sciences
Economics – Microeconomics
Phone: +49 (0) 231/7 55-3297, email: W.Leininger@wiso.uni-dortmund.de
Prof. Dr. Volker Clausen
University of Duisburg-Essen, Department of Economics
International Economics
Phone: +49 (0) 201/1 83-3655, e-mail: vclausen@vwl.uni-due.de
Prof. Dr. Christoph M. Schmidt
RWI, Phone: +49 (0) 201/81 49-227, e-mail: christoph.schmidt@rwi-essen.de
Editorial O ce
Joachim Schmidt
RWI, Phone: +49 (0) 201/81 49-292, e-mail: joachim.schmidt@rwi-essen.de
Ruhr Economic Papers #
Responsible Editor: Christoph M. Schmidt
All rights reserved. Bochum, Dortmund, Duisburg, Essen, Germany, 2011
ISSN 1864-4872 (online) – ISBN 978-3-86788-336-8
The working papers published in the Series constitute work in progress circulated to
stimulate discussion and critical comments. Views expressed represent exclusively the
authors’ own opinions and do not necessarily refl ect those of the editors.

Ruhr Economic Papers #290
Alfredo R. Paloyo, Arndt Rüdiger Reichert,
Holger Reinermann, and Harald Tauchmann
The Causal Link Between
Financial Incentives and Weight Loss
An Evidence-based Survey of the Literature

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bibliografi e; detaillierte bibliografi sche Daten sind im Internet über:
http://dnb.d-nb.de abru ar.
ISSN 1864-4872 (online)
ISBN 978-3-86788-336-8

Alfredo R. Paloyo, Arndt Rüdiger Reichert,
Holger Reinermann, and Harald Tauchmann
1
The Causal Link Between Financial
Incentives and Weight Loss
An Evidence-based Survey of the Literature
Abstract
Obesity and overweight are linked to diseases that cost society a signifi cant amount
of resources. While behavior modifi cation can reduce the problem, instigating such
lifestyle changes is an uneasy task. One potential way to reduce the problem is through
the use of fi nancial incentives. In this survey, we review the available evidence with a
signifi cant emphasis on studies that yield credible estimates of the eff ect of fi nancial
incentives on weight loss. We fi nd that the scientifi c literature on the subject has
not yet satisfactorily settled whether such a mechanism is eff ective at eliciting the
desired behavioral and health outcomes. We therefore advocate a rigorous large-scale
randomized experiment to provide reliable estimates of the eff ect.
JEL Classifi cation: I10, I12, I13, I18
Keywords: Financial incentives; weight loss; obesity; randomized experiment; survey
November 2011
1 Alfredo R. Paloyo, Arndt Rüdiger Reichert, Harald Tauchmann: RWI; Holger Reinermann:
Student Assistant at the Chair of Comparative Politics, University of Cologne. – We thank Viktoria
Frei and Carina Mostert for research assistance. – All correspondence to Arndt Reichert, Rheinisch-
Westfälisches Institut für Wirtschaftsforschung (RWI), Hohenzollernstr.1-3, 45128 Essen, Germany,
E-Mail: arndt.reichert@rwi-essen.de.

Frequently asked questions

Q1. What have the authors contributed in "The causal link between financial incentives and weight loss an evidence-based survey of the literature #290" ?

In this paper, the authors used monetary incentives to encourage individuals to lose weight in developing countries, such as India and China. 

Q2. What have the authors stated for future works in "The causal link between financial incentives and weight loss an evidence-based survey of the literature #290" ?

The possibility of losing money is given much more weight than an equal chance of gaining the same amount of money. 

Q3. What is the main inclusion criteria for an extensive discussion of the results of a study?

Their principal inclusion criterion for an extensive discussion of the results of a study is its experimental design, with a special emphasis on having a genuine control group. 

Q4. How long did Israel and Saccone require the participants to return for weigh-ins?

In a follow-up study, Israel and Saccone (1979) required the participants of the six treatment groups to return for weigh-ins at three and 12 months in order to receive the remainder of a USD 35 deposit. 

Q5. What are the other criteria that the authors consider relevant for the credibility of the results?

The other criteria that the authors consider to be relevant for the credibility of the results are the effectiveness of randomization and the sample size. 

Q6. What is the effect of monetary reinforcement on weight loss?

the authors conclude that monetary reinforcement of a change in eating behavior is more effective than weight loss as the target behavior of the incentive. 

Q7. What are the mechanisms that are susceptible to selection biases?

Assignment mechanisms that are susceptible to selection biases (e.g., based on punctuality at health course meetings, which may be related to participant motivation) are excluded. 

Q8. How much weight loss would a participant receive if they kept their weight?

As an example, if a participant from the steady-payment group lost 5 percentage points of their baseline weight, they would receive USD 35 and a further USD 35 if they maintain their weight six months after the start of the program. 

Q9. What was the average weight loss for the treatment groups?

During the follow-up period, substantial weight regain was found particularly for the treatment groups although the latter still achieved an average net weight loss of 1.2 lbs. 

Q10. What are the criteria for determining the effect of a study?

Rather than direct and incontrovertible evidence, the authors regard the results of studies that do not meet these criteria as coarse measures of the true effect. 

Q11. What is the limitation of this study?

The limitation of this study is that the observed effects may be either due to the financial incentive or the enhanced attention of the medical center for interventiongroup members. 

Q12. How do they find front-loaded participants to lose weight?

For the first three months, Finkelstein et al. find front-loaded participants to lose more weight in absolute terms and to be more likely to lose at least five percent of their body weight than the back-loaded group. 

Q13. How do the authors distinguish their evidence-based review of the literature?

The authors distinguish their evidence-based review of the literature by emphasizing the methodological quality of the surveyed articles and by being explicit both with respect to the type of monetary incentive being analyzed (carrot/positive or stick/negative) and with respect to the outcome (weight loss or weight maintenance after weight loss).