Living Large or Long: Preference Estimates from Completed-Life Stories

Last registered on March 21, 2025
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Pre-Trial

Trial Information

General Information

Title
Living Large or Long: Preference Estimates from Completed-Life Stories
RCT ID
AEARCTR-0015566
Initial registration date
March 14, 2025

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
March 21, 2025, 10:13 AM EDT

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

Locations

Country
United States of America
Region

Primary Investigator

Name
Erzo Luttmer
Affiliation
Dartmouth College
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Other Primary Investigator(s)

PI Name
Amitabh Chandra
PI Affiliation
Harvard University
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PI Name
Joshua Schwartzstein
PI Affiliation
Joshua Schwartzstein
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PI Name
Tomáš Jagelka
PI Affiliation
University of Bonn
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Additional Trial Information

Status
In development
Start date
2025-03-14
End date
2025-12-31
Keywords
Health
Additional Keywords
preference for longevity, survey experiment
JEL code(s)
I10, H51
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
A variety of resource allocation decisions, including in health and environmental policy, depend on how much money people are willing to give up to live an extra year of life. This rate of substitution is typically estimated based on compensating differentials for taking on very small risks of death. We develop an alternative approach to estimate this rate of substitution by presenting respondents on the Prolific platform with pairs of hypothetical life stories, or “vignettes,” that describe complete life courses, and ask them to choose which life they would prefer for themselves. We randomize the lifetime incomes and the ages of death in the vignettes. We present a battery of tests to gauge whether these hypothetical choices measure underlying preferences. The benefit of our method is that it yields estimates of the distribution of preferences for longevity in a representative population, allows for a characterization of heterogeneity in preferences by respondent characteristics, and does not require people to correctly evaluate very small probabilities.
External Link(s)

Registration Citation

Citation
Chandra, Amitabh et al. 2025. "Living Large or Long: Preference Estimates from Completed-Life Stories." AEA RCT Registry. March 21. https://doi.org/10.1257/rct.15566-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
The two key randomizations are: the lifetime income and the age of death in the vignettes shown to respondents. The vignettes and survey instrument contain numerous other randomized interventions that allow us to gauge whether choices over vignettes reflect stable preferences for longevity and to rule out possible confounding factors.
Intervention Start Date
2025-03-14
Intervention End Date
2025-07-14

Primary Outcomes

Primary Outcomes (end points)
Choice of vignette within a pairs of vignettes (= completed-life stories of about two to three paragraphs in length) where the life-time incomes and longevity of the protagonists in the vignettes is randomized.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The longevities and life-time incomes of the protagonists shown in the vignettes are independently randomized across respondents and vignettes, except that in wave 2 of the survey we present the respondent with one vignette pair that is identical (and has identical randomizations) to one randomly selected vignette pair that the respondent saw in wave 1.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer.
Randomization Unit
The randomization for longevities and life-time incomes of the protagonists in the vignettes occurs at the (vignette)*(respondent)*(question number) level. Thus, each time a respondent sees a vignette, the longevity and life-time income of the protagonist is randomly drawn for that vignette, that respondent, and that question number. So, if a respondent sees the same vignette more then once (say, in different waves of the survey), the longevity and life-time income of the protagonist will be re-randomized. There is one exception: In wave 2 of the survey, we present the respondent with one vignette pair that is identical (and has identical randomizations) as one randomly selected vignette pair that they saw in wave 1.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
The planned analysis sample consists of 27,500 choices of a vignette within a vignette pair.

Details:
We aim for a sample size of 3750 respondents in wave 1. We expect 75% of these respondents, so about 2800 of them, to pass the sample inclusion criteria. The sample inclusion criteria are are pre-specified in the analysis plan. We invite only respondents who passed the inclusion criteria in wave 1 to take wave 2. Based on our estimated response rate, we expect to re-survey about 2400 respondents in wave 2. This brings the sample size in the two waves combined to about 6150 respondent*wave observations.

We expect that about 75% of respondent*wave observations pass our inclusion criteria. Thus, the analysis sample will be about 4600 respondent*wave observations.

Within a each wave, each respondent is asked six times to choose one vignette out of a pair of vignettes. Hence, we obtain 6 choices per respondent per wave. This brings the expected number of units of observation to about 27,500.
Sample size: planned number of observations
The planned analysis sample consists of 27,500 choices of a vignette within a vignette pair. Further details: See the explanation given under "planned number of clusters." The choices are made in about 4600 respondent*wave observations by about 2800 unique respondents.
Sample size (or number of clusters) by treatment arms
There are no treatment arms; the longevity for the protagonist in a (vignette)*(respondent)*(question number) observation is randomized between all ages from 60 to 90 and the protagonist's income is drawn randomly from all annual income levels (rounded to the nearest $1000) that fall within 33% of the baseline income in a given vignette (the baseline income level in a vignette is chosen so that it is realistic for the protagonist's occupation).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Dartmouth College Committee for the Protection of Human Subjects
IRB Approval Date
2022-12-16
IRB Approval Number
STUDY00032638
IRB Name
Harvard University-Area Committee on the Use of Human Subjects
IRB Approval Date
2023-01-11
IRB Approval Number
IRB22-1623
Analysis Plan

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