We used case study methods to more fully understand the effects of parity from the perspectives of these groups. Case study analyses of parity describe informants' judgments about the effects of parity and provide information more quickly than statistical analyses. But unlike statistical analyses, they cannot be used to estimate the costs of parity or provide the percentage of organizations that are affected.
Statistical studies require detailed health expenditure data before and after parity is implemented.
In addition, for comparison purposes, statistical studies require health expenditure data from employers that have implemented parity and those who have not. We wanted each state to have at least one year of experience with parity. From May through July 1997, we contacted 47 organizations in the study states, including insurers, employers, employer associations, and public officials, such as representatives from the state departments of mental health and substance abuse. We also spoke with provider associations, such as state psychiatric associations, and consumer and family advocates. We spoke with more organizations in states with broader laws.