Improvements on valuing gains in health status with stated preferences

Last registered on November 01, 2023


Trial Information

General Information

Improvements on valuing gains in health status with stated preferences
Initial registration date
October 21, 2023

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
November 01, 2023, 2:36 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.


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Primary Investigator

Universite Paris-Dauphine

Other Primary Investigator(s)

PI Affiliation
PI Affiliation
Harvard University

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This project is motivated by the increasing need for economic tools enabling French authorities to rank policies that seek to reduce risks to life and limb. As of 2012, the multi-annual French public budget programming bill requires that for all publicly funded investments a full socioeconomic evaluation be carried out before implementation. Government agencies around the world, including French authorities, typically employ estimates of the value per statistical life (VSL) to quantify the benefits of regulation-induced or investment-induced changes in mortality risk. In the socioeconomic evaluation sphere, VSL is one of the most influential metrics.

A first objective of our research aims at empirically eliciting both the VSL and the WTP for improved quality-of-life in France, as well as the bounds on the WTP for improved quality-of-life. The project’s second objective is to provide empirical support for an innovative method for estimating VSL in stated preferences surveys: the use of non-marginal risk reductions.
External Link(s)

Registration Citation

Hammitt, James, Daniel HERRERA ARAUJO and Christoph Rheinberger. 2023. "Improvements on valuing gains in health status with stated preferences." AEA RCT Registry. November 01.
Sponsors & Partners

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Experimental Details


The project ANR-20-CE36-0010-01 (VHEALTH hereafter) aims at providing new tools to assess monetary values for improved health and longevity. Our research aims at empirically identifying the upper and lower bounds for the value of improved health and longevity along with VSL estimates in France. The project's second objective aims at providing empirical support for an innovative method for estimating the VSL through SP: the use of non-marginal risk reductions. Most papers ask respondents to value small risk reductions to elicit VSL. These have the advantage that under conventional theoretical assumptions, WTP should be nearly proportional to the proposed risk reduction for small risk reductions.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
There are three primary outcomes:
The willingness to pay elicited. Within the WTP task, we ask respondents to consider a status-quo situation described by five attributes: (1) risk of developing cancer and dying from it; (2) risk of developing cancer and recovering from it; (3) quality-of-life conditional on having cancer; (4) duration of cancer spell; and (5) cost for buying regular food products. Respondents are asked to compare it with a scenario where, at a higher cost, the ‘risk of developing cancer and dying from it’ and/or the ‘risk of developing cancer and recovering from it’ are reduced via the purchase of /safety-certified food products.

The standard gamble. The standard gamble asks respondents to assume that they are diagnosed with cancer and two alternative treatments are available: a low-risk (or no risk) treatment that allows them to (nearly) avoid death from cancer, but with which their health status remains compromised for a specified duration; or a high-risk experimental treatment that is highly effective in some people but not effective in others. We assign half of the respondents to a "no-risk" vs. "high- risk" treatment, while the other half are assigned to a "low-risk" vs. "high-risk" treatment. The "low-risk" treatment randomly assigns between a risk of 1 in 1000 or 2 in 1000 of dying, even if taking the treatment.

Following the WTP question, the standard gamble and some debriefing questions, respondents receive, at random, one of three alternative sets of questions about hypothetical financial risks. The first set of questions will follow Barsky et al. (1997) elicitation for risk aversion. Following Hammitt & Haninger (2010), a second set of questions instructs respondents to
decide about two job offers. Specifically, they can choose between a salary job, which pays an annual salary that increases modestly each year, and a bonus job, which pays a smaller salary but offers with some probability a large annual bonus. Finally, we adapt a version of the Eckel and Grossman risk elicitation task (2002, 2008) which consists of asking subjects to choose their preferred gamble from among six possible choices.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary outcomes are respondents self-assess health.
Secondary Outcomes (explanation)
Current health is elicited using either a visual analog scale (VAS) on which 100 corresponds to full health and 0 to a health state equivalent to death, or the EQ-5D health state classification system (EuroQol Group, 1990). The EQ-5D is a utility instrument used to quantify the health-related quality of life (HRQL) associated with an individual’s current health or a hypothetical health state. It classifies health states using five dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression), each of which can take any of three levels (no, moderate, or severe problems) (or five levels in a newer version). HRQL is an index normalized to a value of one for full health and zero for health states an individual judges indifferent to being dead (negative values are permitted). It can be estimated from the EQ-5D health-state description using a scoring rule (Andrade et al., 2020).

Experimental Design

Experimental Design
Reported in the PAP.
Experimental Design Details
Not available
Randomization Method
Reported in the PAP.
Randomization Unit
Individual level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
5150 respondents.
Sample size: planned number of observations
5150 respondents.
Sample size (or number of clusters) by treatment arms
We plan around 170 respondents per block.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Comité d’Éthique de la Recherche - University Paris Dauphine
IRB Approval Date
IRB Approval Number
FF/KB – 20230710/02
Analysis Plan

Analysis Plan Documents


MD5: b9c83cc55e99b6257d099024879c6dfe

SHA1: 9f706d19df92b357077295e332d87327ab95745e

Uploaded At: October 21, 2023