Quality signals in health care: a vignette experiment in South Africa

Last registered on November 30, 2021

Pre-Trial

Trial Information

General Information

Title
Quality signals in health care: a vignette experiment in South Africa
RCT ID
AEARCTR-0008443
Initial registration date
October 25, 2021
Last updated
November 30, 2021, 2:20 PM EST

Locations

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Primary Investigator

Affiliation
LSE

Other Primary Investigator(s)

PI Affiliation
LSE
PI Affiliation
University of the Witwatersrand

Additional Trial Information

Status
In development
Start date
2021-10-26
End date
2021-12-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Overtreatment is widespread in health care, including in low- and middle-income settings. In primary care, providers often recommend unnecessary drugs, with potential dire consequences for patients, health systems and public health. Recent evidence suggests that providers recommend unnecessary treatment even in the absence of direct financial incentives and when they know what the appropriate treatment is. Providers have sometimes explained their decisions to overtreat as a response to an actual or perceived demand from patients, who, in a relationship characterized by asymmetry of information, may interpret treatment characteristics as a signal of quality. We design a simple vignette experiment to test (1) whether reduced overtreatment is perceived as a signal of worse quality of care and (2) the relevance of the treatment signal against another typical signal of quality care (thoroughness of the consultation).
External Link(s)

Registration Citation

Citation
Blaauw, Duane, Mylene Lagarde and Nicholas Stacey. 2021. "Quality signals in health care: a vignette experiment in South Africa." AEA RCT Registry. November 30. https://doi.org/10.1257/rct.8443-1.1
Experimental Details

Interventions

Intervention(s)
In a survey experiment respondents see and rate one clinical vignette depicting the story of a patient suffering from a minor lower-respiratory tract infection (acute bronchitis) who decides to consult a doctor. Our design cross-randomizes variation in the type of treatment recommended by the doctor with information about the thoroughness of the consultation, in a 5x2 design. Along the treatment dimension, each respondent sees one of five possible treatment outcomes:
- No drugs prescribed
- Two Over-the-Counter (OTC) drugs prescribed
- Four OTC drugs prescribed
- Two drugs prescribed: one prescription drug (antibiotic) and one OTC drug.
- Four drugs prescribed: two prescription drugs (antibiotic and steroids) and two OTC drugs.

Along the second dimension, we randomize the amount of information about the technical quality of the consultation process. For respondents assigned to receiving some information about the consultation, the vignette includes a summary of the questions asked by the providers and physical examinations undertaken.
Intervention Start Date
2021-10-26
Intervention End Date
2021-12-31

Primary Outcomes

Primary Outcomes (end points)
The main outcomes of interest are the first-order beliefs of respondent, judging different aspects of quality of care. The main outcome is a rating of the provider’s competence on a scale of 1-4.
Other outcomes of interest include rating of the effectiveness of care received, the treatment safety, and satisfaction with the provider (likelihood to us the same doctor again).
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary outcomes include second-order beliefs of the same four dimensions quality of care, which are incentivised.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
This survey experiment is embedded in a broader survey looking at provider preferences and the demand for healthcare. Survey respondents are part of an online panel in South Africa, aged 18-65, who do not have a medical health insurance. Respondents see and rate one clinical vignette depicting the story of a patient suffering from a minor lower-respiratory tract infection (acute bronchitis) who decides to consult a doctor. The design cross-randomizes variation in the type of treatment recommended by the doctor with information about the thoroughness of the consultation, in a 5x2 design. Along the treatment dimension, each respondent sees one of five possible treatment outcomes:
- No drugs prescribed
- Two Over-the-Counter (OTC) drugs prescribed
- Four OTC drugs prescribed
- Two drugs prescribed: one prescription drug (antibiotic) and one OTC drug.
- Four drugs prescribed: two prescription drugs (antibiotic and steroids) and two OTC drugs.
Along the second dimension, we randomize the amount of information about the technical quality of the consultation process. For respondents assigned to receiving some information about the consultation, the vignette includes a summary of the questions asked by the providers and physical examinations undertaken.
Experimental Design Details
Not available
Randomization Method
Survey platform random number generator.
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1800
Sample size: planned number of observations
1800
Sample size (or number of clusters) by treatment arms
180 individuals per clinical vignette presentation.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
The design is powered to detect a 0.3 standard deviation effect.
IRB

Institutional Review Boards (IRBs)

IRB Name
University of the Witwatersrand Human Research Ethics Committee (Non-medical)
IRB Approval Date
2021-09-15
IRB Approval Number
H21/07/49