The Effects of Switching Electronic Health Record Developer on Specialty Referrals

We use national physician-pair panel data to examine how switching electronic health record (EHR) developers affects out-of-network referrals from primary care physicians (PCPs) to specialists. We estimate a difference-in-differences model, exploiting changes in EHR developer adoption by physicians’ affiliated hospitals. After a change in the PCP’s EHR developer, referrals to same-developer specialists increase by 5.8%, and referrals to specialists using the PCP’s prior EHR decrease by 4.2%. Referrals to the PCP’s most commonly referred-to specialists are not affected by changes in EHR developer, but shifts in referral patterns are particularly pronounced when the PCP is male and the specialist is female, when the PCP has more experience than the specialist and when the new EHR developer has a majority market share. These results are robust to estimation approaches that account for heterogenous treatment effects and physician selection into hospital systems. Our theoretical model indicates that PCP preferences for convenience may reduce referrals to the highest-quality specialists and lead to EHR market agglomeration, presenting a possible economic rationale for antitrust regulation of information blocking.