Primary care Medicaid physician fee generosity and access to board certificated physicians across skill levels

Objective

Measure association between Medicaid fee generosity for primary care services and access to board certified primary care internists across skill levels.

Approach

Sample: Private practice board certified internists 10 years past their residency.

Skill measures: Residency evaluation ratings and initial board certifying examination performance.

Access measure: Share of patients Medicaid insured

Surveys completed by internists as part of their recertification requirement (85% response rate). Survey includes share of practice Medicaid insured.

Primary care fee measure was from 2008 and 2012 surveys of state Medicaid fees. Fees were divided by the Medicare equivalents to account for regional difference in costs.

Method: Applying a two part state fixed effects model (any Medicaid insured, conditional on any, share Medicaid insured), we estimated the relationship between share Medicaid insured and: Medicaid fee generosity interacted with physician skill indicators.  State indicators accounted for state characteristics that were correlated with our fee measure but are constant over time, a 2008 indicator to accounted for factors that vary over time other controls accounted for patient demand.

Findings

An increase in the primary care Medicaid/Medicare fee ratio (mean=.60) of 25 percentage points was associated with a 1.4 percentage point (P=.043) increase in the share of Medicaid insured in a physician’s practice (18% increase).

A skill-fee interaction term coefficients indicated that this association was 2.1 percentage points larger for physicians with top residency evaluations than poorer evaluations; and 1.1 percentage point larger for physicians with certification examination score in the top quartile than those lower quartiles (Ps<.05).