procedure specific volume (continuous and quintile)
Volume of all GU procedures (continuous and quintile)
hospital bed number
hospital type (academic/not)

safety net as defined by medicare DSH as highest quartile
See: Matlin Gilman, E. Kathleen Adams, Jason M. Hockenberry, Ira B. Wilson, Arnold S. Milstein and Edmund R. Becker. California Safety-Net Hospitals Likely To Be Penalized By ACA Value, Readmission,

And Meaningful-Use Programs Health Affairs, 33, no.8 (2014):1314-1322)

when making training set, instead of taking random sample across entire dataset, group by hospital and sample randomly from within that hospital to ensure all hospitals present in training AND testing data

based on some metric from other data (SEER medicare, NCDB, NIS), not our own data

recently obtained from OSHPD: patient mortality data

will make interpreting regression results easier

import medicare Provider of Services data, # of resident FTE per hospital, academic yes/no
https://www.cms.gov/Research-Statistics-Data-and-Systems/Downloadable-Public-Use-Files/Provider-of-Services/POS2007.html

Combine single factor models with multi factor grouped models into single markdown file