On the Impact of Social Comparison on Physician Behavior
Last registered on September 30, 2019

Pre-Trial

Trial Information
General Information
Title
On the Impact of Social Comparison on Physician Behavior
RCT ID
AEARCTR-0004747
Initial registration date
September 25, 2019
Last updated
September 30, 2019 5:28 PM EDT
Location(s)

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Primary Investigator
Affiliation
University of Bern
Other Primary Investigator(s)
PI Affiliation
Erasmus University Rotterdam
PI Affiliation
Erasmus University Rotterdam
PI Affiliation
University of Bern
Additional Trial Information
Status
In development
Start date
2019-11-01
End date
2021-09-01
Secondary IDs
Abstract
Primed by the ongoing political and academic debate about rising health costs and the over-provision of medical care in the developed world, this research project strives at gaining an in-depth understanding about how the provision of social comparison information influences physician behavior, adherence to clinical guidelines and quality of care. To this end, we are planning to run a pragmatic randomized trial in which general practitioners (GPs) from the universe of all GPs active in the outpatient sector in Switzerland are randomly assigned to either an intervention group receiving social comparison letters or the control group (no letter). The information in the social comparison letters is extracted from routinely collected insurance claims data and contains information about the health care costs or practice style behavior (e.g. vaccination rate, generic drug use) of a GP in comparison to peers with a comparable risk pool of patients. Previous studies have shown that peer comparison information has the potential to significantly influence individual decision-making in various contexts thereby motivating the extension to the proposed physician population (e.g. Meeker et al., 2016; Allcott & Rogers, 2014).
External Link(s)
Registration Citation
Citation
Gerfin, Michael et al. 2019. "On the Impact of Social Comparison on Physician Behavior." AEA RCT Registry. September 30. https://doi.org/10.1257/rct.4747-1.1.
Experimental Details
Interventions
Intervention(s)
We randomly draw general practitioners (GPs) from the universe of all primary care providers active in the outpatient sector in Switzerland to receive peer comparison letters containing information on either their health care expenditures and/or practice style behavior (vaccination or generic drug rates) in comparison to GPs with a comparable risk pool of patients. Primary care providers in the control group receive no social comparison letter.

The letter will be sent out once at the beginning of the intervention period and the short-term reaction is tracked after half a year. To capture the long-term response, information on the main outcomes will be gathered again after one year.
Intervention Start Date
2020-01-06
Intervention End Date
2020-02-03
Primary Outcomes
Primary Outcomes (end points)
Primary outcomes of the field experiment are the health care costs (plus cost subcategories) and practice style indicators including the influenza vaccination rate and generic drug rate of GPs active in the Swiss outpatient sector.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
Nation-wide pragmatic randomized trial using a full factorial design allocating physicians to either the control or one of the intervention arms receiving peer comparison information.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer
Randomization Unit
Individual level: Primary care providers active in the Swiss outpatient sector
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
6300 primary care providers
Sample size: planned number of observations
6300 primary care providers
Sample size (or number of clusters) by treatment arms
1600 GPs in the control group (no letter); 1600 GPs in the generic drug rate intervention group; 1500 GPs in the influenza vaccination intervention group; 1600 in the health care cost intervention group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
WISO Faculty's ethics committee (University of Bern)
IRB Approval Date
2018-05-31
IRB Approval Number
N/A