TABLE 1.

Predictors included in the synthetic control construction

Variable	Source	Average	Standard deviation
(1) Receipt of mental health services among children (percentage).	Denominator: Children aged 2‐17 years who had an ongoing emotional, developmental, or behavioral problem that, in the view of their parents, required treatment or counseling. Numerator: Children that received mental health services in the past year. Based on nationally representative survey of parents, conducted by Maternal and Child Health Bureau, Health Resources and Services Administration (HRSA). 27	62.1	8.2
(2) Mental health professional shortage (percentage).	Denominator: Minimum number of providers necessary in the state to meet the mental health needs, determined by HRSA. Numerator: Gap between minimum necessary and actual number of providers (lower percentages reflected less shortage). 28	34.4	14.9
(3) Clinically informed prescriber feedback system	Availability of a prescriber feedback systems such as prescription reviews, prescribing performance letters, based National Alliance on Mental Illness survey of mental health authorities. 29 Five‐point Likert scale (0‐4), smaller numbers representing limited efforts (eg, limited programs and feedback that is not prescriber specific).	3	1.4
(4) Percent living in urban areas	US 2010 Census 30	74.1	14.9

Average and standard deviations were presented for all 50 states and District of Columbia.