Date: 23 May, 2019

Dataset Title: Effect of financial incentives on head CT use dataset

Dataset Creators: William Meurer

Dataset Contact: wmeurer@med.umich.edu

Funding: National Institutes of Health (NIH)


Research Overview:
We conducted a cross-sectional survey of patients at the University of Michigan Emergency Department (ED). Each participant was presented with a hypothetical scenario involving an ED visit following minor traumatic brain injury, and a scenario involving chest pain. Participants were given information regarding potential benefit (detecting brain hemorrhage) and risk (developing cancer) of head CT scan, as well as an incentive of $0 or $100 to forego testing. We used 0.1% and 1% for test benefit and risk, and values for risk, benefit, and financial incentive varied across participants. Our primary outcome was patient preference to undergo testing. We also collected demographic and numeracy information. Then, we used logistic regression to estimate odds ratios, which were adjusted for multiple potential confounders. Our sample size was designed to find at least 300 events (preference for testing) to allow for inclusion of up to 30 covariates in fully adjusted models. We had 85-90% power to detect a 10% absolute difference in testing rate across groups, assuming a 95% significance level. 

The University of Michigan Institutional Review Board reviewed this study and determined it to be exempt survey research. 


Methodology:
This is a cross-sectional survey of a convenience sample of patients from the University of Michigan Emergency Department. Each participant was randomly assigned a value for benefit (0.1% or 1%), risk (0.1% or 1%), and incentive ($0 or $100) associated with a head CT scan. Participants were provided with percentages (0.1% or 1%), ratios (1 in 100 or 1 in 1000), and visual depictions of risk and benefit values to improve comprehension.

After consent was obtained, a script of the scenario was read aloud to all participants to limit possible issues they might have with reading, seeing, or comprehending the scenario. 

For a full description of study methodology, please see the associated article (and Appendix A of the published version of the article).


Dates of study: May-July 2016


Instrument and/or Software specifications:
Qualtrics was used for survey administration and data collection, and SPSS version 24 was used for data analysis.


Files contained here: 

-Rahul2016DiagnosticAccuracyUMHS2019Apr23.sav - the survey responses for the 913 patients who met inclusion criteria and completed the survey, as processed in SPSS.

-2016DiagnosticAccuracyUMHS_May+23,+2019_12.47.csv - CSV version of raw data prior to manipulation.

-2016DiagAccuracyInstrument.pdf - a PDF version of the Qualtrics survey instrument (without survey logic or question numbers).

-2016DiagnosticAccuracyUMHS.docx - The Qualtics survey instrument with survey logic and question numbers (which map to variables in dataset).

-OUTPUT23aPRIL2019.doc - outputs of the nested multivariable logistic regression models used to calculate the odds that participants would agree to receive a head CT scan. Note that model numbers as noted in the output may not match to model numbers as cited in the related publication.

FILES ADDED AUG. 26, 2019
-OUTPUTunadjustedCP.doc - This is SPSS output from the unadjusted logistic regression models for cost, benefit, and risk for the chest pain outcome.

-aug23adjustedmodels.doc - This is the SPSS output from models 1 – 4 including adjustment for patient level factors for the chest pain outcome.


**Note that the model itself is not included in this dataset.
Missing data are indicated by ".", and some internal Qualtrics variables are completely blank as this information was not collected.


Related publication(s):
Iyengar, R., Winkels, J., Smith, C. M., Meka, A. P., MD, Porath, J. D., MD, & Meurer, W. J., MD, MS. (2019, January 21). The Effect of Financial Incentives on Patient Decisions to Undergo Low-Value Head CT Scans. https://doi.org/10.31219/osf.io/4mdfw


Use and Access: 
This data set is made available under a Creative Commons Attribution-NonCommercial 4.0 International license (CC BY-NC 4.0).


To Cite Data: 
Meurer, W. (2019). Effect of financial incentives on head CT use dataset [Data set]. University of Michigan Deep Blue Data Repository. https://doi.org/10.7302/pnmm-4v40