Farley 2008

Methods	Controlled ITS measured per member per month
Participants	Intervention: Georgia N=5178 Medicaid members n=984,843; control: Mississippi members N=2218 (no restriction) Medicaid members n= 434,782
Interventions	To document effect of step therapy PA policy for atypical antipsychotics
Outcomes	Health services utilization, drug costs
Notes	Jan 1‐1996‐Dec 31 1997 modeled 10 months pre‐policy, 11 months policy period (long transition period), 3 months post‐policy
Risk of bias
Bias	Authors' judgement	Support for judgement
Incomplete outcome data (attrition bias) All outcomes	Low risk	Any undocumented difference in the proportion of missing data in the administrative datasets pre‐ and post‐intervention is unlikely to overturn study results
Selective reporting (reporting bias)	Low risk	All outcomes listed in the methods section are reported in the results section
Other bias	Unclear risk	Unclear as it is difficult to evaluate model assumptions Dementia was included as a condition of interest (along with schizophrenia, bipolar, depression and other mental health conditions) even though antipsychotics are not recommended in dementia, because they are commonly used to control symptoms.
Knowledge of allocated interventions adequately prevented during the study	Low risk	Outcomes are objective measures of healthcare utilization
Intervention independent of other changes	Unclear risk	"Our study examined a period of adoption for atypical antipsychotic medications. The atypical antipsychotic olanzapine, for example, was approved by the US Food and Drug Administration during the prepolicy period shortly before the policy was enacted."
The shape of intervention pre‐specified?	Low risk	The point of analysis is the point of intervention; ie, the date the policy intervention was implemented was used to delineate pre and post policy time periods with adequate data points to capture the shape of the pattern of intervention effect over time
Intervention unlikely to affect data collection?	Low risk	Sources and methods of data collection were the same before and after the intervention