Economy plus medicine! - Hamburg's health research opens up (OPEN!)

Last registered on April 13, 2023

View Trial History

Pre-Trial

Trial Information

General Information

Title

Economy plus medicine! - Hamburg's health research opens up (OPEN!)

RCT ID

AEARCTR-0011099

Initial registration date

April 06, 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

April 13, 2023, 3:51 PM EDT

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

Locations

Country

Germany

Region

Hamburg

Primary Investigator

Name

Claudia Schwirplies

Affiliation

Philipps University Marburg

Contact Primary Investigator

Other Primary Investigator(s)

PI Name

Lorenzo Romero

PI Affiliation

University of Hamburg

Contact Investigator

Additional Trial Information

Status

In development

Start date

2023-04-07

End date

2023-04-23

Keywords

Behavior, Health

Additional Keywords

health equity

JEL code(s)

Secondary IDs

Prior work

This trial does not extend or rely on any prior RCTs.

Abstract

Research shows that people with low socio-economic status (SES) in particular are less likely to participate in health studies. However, in order to be able to transfer the study results to the general population, it is important to reach a representative group of people. This is the only way that all strata of society can benefit from new medical findings as well as preventive and treatment options. Although studies to date have highlighted the problem of underrepresentation of people with low SES, little research has been done on possible solutions for reaching all social groups for health research. Other strands of literature show that people with low SES have lower levels of trust and present-biased preferences.
The RCT is part of a transfer project in cooperation with the Universitätsklinikum Hamburg-Eppendorf (UKE) and aims at identifying factors that motivate people with low SES to take part in health research. For this, we send out letters to former participants of the Hamburg City Health Study (HCHS) to invite them to come to the open-doors day and participate in a survey on motives for participating in health research. The former participants will be randomly assigned to 5 different groups receiving different letters with text modules designed to generate trust in health research or communicate the personal/societal benefits of health research. Our hypotheses are that lack in trust and present-biased preferences prevent low SES citizens from participation in health research. That is, we expect that generating trust and emphasizing the private benefits of more people participating in health research already today, will increase the participation of people with low SES in (a) the survey, (b) the open-doors day, and (c) a planned idea workshop (where participants can get more involved in the conception and implementation of health studies), while emphasizing future private benefits public benefits will not.

External Link(s)

Registration Citation

Citation

Romero, Lorenzo and Claudia Schwirplies. 2023. "Economy plus medicine! - Hamburg's health research opens up (OPEN!)." AEA RCT Registry. April 13. https://doi.org/10.1257/rct.11099-1.0

Sponsors & Partners

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information

Experimental Details

Interventions

Intervention(s)

Former participants in the HCHS will be randomized into 5 groups and will receive invitation letters to the open-doors day. This letter will contain a request to participate in a survey about the factors motivating or preventing people from taking part in health research. The 5 groups will receive different text modules designed to generate trust in health research or communicate the personal/societal benefits of health research (translated from the original treatment modules in German):

(i) Control: In order to apply the HCHS study results to the general population, it is important that we reach as many people as possible.

(ii) Trust in health research: In order to apply the HCHS study results to the general population, it is important that we reach as many people as possible. For this reason, Hamburg Health Research is opening up further and, with the Ideas Workshop, is developing a new opportunity to enter into an exchange with you and other participants.

(iii) Private benefits today: In order to apply the HCHS study results to the general population, it is important that we reach as many people as possible. In this way, you too can benefit personally from new medical findings, prevention and treatment options.

(iv) Private benefits future: In order to apply the HCHS study results to the general population, it is important that we reach as many people as possible. In this way, you too will personally benefit from new medical findings, prevention and treatment options in the future.

(v) Public benefits: In order to apply the HCHS study results to the general population, it is important that we reach as many people as possible. In this way, tomorrow's medicine and society will benefit from new medical findings, prevention and treatment options.

Intervention Start Date

2023-04-07

Intervention End Date

2023-04-23

Primary Outcomes

Primary Outcomes (end points)

As outcome variables we will measure survey participation, coming to the open-doors day, and stated interest in the planned idea workshop per treatment group (i.e. the different text modules).

Primary Outcomes (explanation)

Participation in the open-doors day will be tracked via markers on the invitation letter.
Interest in the planned ideas workshop will be tracked by an expression of interest via a contact form.

Secondary Outcomes

Secondary Outcomes (end points)

Manipulation checks: Level of Trust in the health reseach, beliefs in public and private benefits of the HCHS.
Heterogeneity analyses will be conducted with respect to socio-economic status.

Secondary Outcomes (explanation)

We use established scales to measure trust using several items.
We ask participants about their agreement to the statement that participants benefit from the participation in the HCHS already today, that participants will benefit from the participation in the HCHS in the future, and that the society as a whole benefits from the participation in the HCHS.
Socio-economic status (SES) is measured by education, occupation (particularly the physiological, psychological, and perceived health burden associated with the occupation), and household net income. Wealth is also used as an indicator for SES. However, since we expect numerous missing answers to questions about wealth, we do not include it as an indicator. The final indicator is migration. We include a question about the country of birth. However, only people with sufficient German language skills can participate in the HCHS, such that migration disadvantage is also difficult to assess.

Experimental Design

Experimental Design Details

Randomization Method

Randomization of former participants into 5 groups in done via computer at the UKE.

Randomization Unit

individual

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

none

Sample size: planned number of observations

Letters will be sent out to around 14,000 former participants, i.e. 2,800 per group.

Sample size (or number of clusters) by treatment arms

About 2,800 former participants of HCHS in each treatment group.

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

We expect that in the control group 10% (p1 = 0.1) participate in our survey. This expectation relies on former studies of the UKE with the same sample. The power analysis is based on a two-sample proportions test with H0: p2 = p1 versus Ha: p2 != p1; p2 > p1. Study parameters: alpha = 0.05 power = 0.80 N per group = 3,000 p1 = 0.10 Estimated effect size and experimental-group proportion: delta = 0.0236 (difference) p2 = 0.1236 For coming to the open-doors day or stating interest in the planned ideas workshop, we expect 1% = 28 people response respectively. Study parameters: alpha = 0.05 power = 0.80 N per group = 2,800 p1 = 0.01 Estimated effect size and experimental-group proportion: delta = 0.0089 (difference) p2 = 0.0189 Heterogeneity analysis with low SES group: In Germany (similarly in the City of Hamburg), around one in six people is considered socially disadvantaged or at risk of poverty. Assuming that this proportion is underrepresented in our sample and that this population group is also less likely to participate in our study in the control treatment, we assume N = 300 per treatment group with p1 = 0.05. Under these assumptions, we could identify a difference of delta = 0.1, i.e., p2 = 0.15 with alpha = 0.05 and power = 0.80. Since such a large effect is not expected with our treatments, we will employ a difference-in-difference estimation with p1 = difference between low SES people and other participants in the control group and p2 = difference between low SES people and other participants in the treatment group. Study parameters: +--------------------------------------------------------------------------------+ | alpha power N N1 N2 delta p1 p2 | |----------------------------------------------------------------------------------| | .05 .8 5,600 2,800 2,800 .00894 .01 .01894 | | .05 .8 5,600 2,800 2,800 .0119 .02 .0319 | | .05 .8 5,600 2,800 2,800 .01414 .03 .04414 | | .05 .8 5,600 2,800 2,800 .016 .04 .056 | | .05 .8 5,600 2,800 2,800 .01761 .05 .06761 | +--------------------------------------------------------------------------------- +

Supporting Documents and Materials

IRB