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. Author manuscript; available in PMC: 2017 Dec 1.
Published in final edited form as: J Health Econ. 2016 Sep 30;50:131–143. doi: 10.1016/j.jhealeco.2016.09.009

Table 3.

Interrupted time series segmented regression analysis: estimates of the change in penetration rates and conditional means of expenditures and utilization associated with federal parity, comparing the post period to the pre-parity period.

Change in Penetration Rate1 Change in Conditional Mean2
Outcome Δ Level3 P-value Δ Slope4 P-value Δ Level3 P-value Δ Slope4 P-value
Expenditures
    Total 0.00028 0.86 −0.00014 0.01 $31.37 0.07 −$0.59 0.42
    Plan 0.00024 0.89 −0.00010 0.16 $58.03 0.00 −$0.17 0.82
    Patient Out-Of-Pocket −0.00323 0.04 −0.00023 0.00 −$21.58 0.03 −$0.33 0.38
Outpatient Visits
    Assessment/Diagnostic Evaluation 0.00008 0.70 −0.00002 0.02 0.005 0.86 −0.001 0.42
    Medication Management 0.00017 0.68 −0.00004 0.03 −0.008 0.80 0.000 0.70
    Individual Psychotherapy −0.00045 0.71 −0.00008 0.06 −0.030 0.53 −0.002 0.49
    Family Psychotherapy 0.00006 0.73 −0.00002 0.00 −0.049 0.45 −0.001 0.47
Days of Intermediate Care
    Structured Outpatient 0.00012 0.03 0.00000 0.19 −0.275 0.48 0.013 0.28
    Day Treatment 0.00002 0.30 0.00000 0.70 0.570 0.28 0.016 0.43
    Residential 0.00002 0.29 0.00000 0.49 1.443 0.07 0.003 0.91
Days of Inpatient Care 0.00007 0.01 0.00000 0.63 0.008 0.98 −0.003 0.79

Notes: Sample is person-months from 2008-2013 (full sample N=49,968,367). Bold denotes significance at p≤.05. Regressions controlled for a linear monthly time trend, indicators and splines for both the transition and post periods, sex, age group, whether the enrollee was the primary insured person, employer group size category, plan type, state fixed effects, provider supply measures, and seasonality.

1

Estimates are from logistic regression marginal effects post-estimation; p-values are from logistic regression.

2

Estimates and p-values are from gamma regression marginal effects post-estimation.

3

Discontinuity (change in level) at the beginning of the post period, as measured by an indicator variable for the post period.

4

Spline (change in slope) for the post period.