The study design included selecting a small number of plans for in-depth study, i.e., obtaining archival claims data, conducting plan site visits, and conducting focus groups with providers (from a subset of the selected plans). Plans were selected on the basis of various characteristics on which they were likely to differ:
- geographic location;
- the breadth of parity in State law;
- differences in plan type and structure (e.g., health maintenance organization [HMO], point of service [POS], or fee-for-service [FFS] with a preferred provider option [PPO]);
- size of the enrollee population; and
- the plan’s interest in collaborating on the evaluation.
Based on these considerations, the following eight plans were selected for site visits:
- Fee-for-service national plan (FFS-NAT),
- HMO West #1 plan (HMO-W1),
- Fee-for-service West plan (FFS-W),
- Fee-for-service Mid-Atlantic #1 plan (FFS-MA1),
- Fee-for-service Mid-Atlantic #2 plan (FFS-MA2),
- Fee-for-service South plan (FFS-S),
- HMO Northeast plan (HMO-NE), and
- HMO West #2 plan (HMO-W2).10
The first nine plans (excluding HMO-W2) that contributed to the impact analysis that comprises chapter IV represent a total of 3,209,617 FEHB beneficiaries. The FFS-NAT is a very large national fee-for-service (FFS) plan covering over a million lives. HMO-W1 is an HMO, and HMO-NE is an HMO with a POS option within the FEHB Program. The remaining six plans are licensees of a large national association (the “Association”). All six are FFS plans with a PPO, managed in somewhat different ways in each location by a variety of managed behavioral health care organization (MBHO) vendors11. Individual Association plans were selected to represent a range of geographic locations with large numbers of beneficiaries.
For two additional plans, FFS-NE1 and the FFS-NE2, the PERT collected utilization and cost data but was unable to obtain detailed implementation data due to resource constraints.
Because of the small number of selected plans, this represents a purposive sampling process, rather than random sampling. It was intended to produce a sample roughly representative of all the FEHB plans with 500 or more enrollees, along the qualitative dimensions just described.
Procedures to Ensure Confidentiality
The PERT maintained confidentiality for all data collected in the study. Site visit interviews were summarized anonymously in all study materials. For the archival data analysis, each participating health plan created scrambled participant identification numbers; deleted names, addresses, and other unique identifiers; and sent the claims data file to the PERT. When requested, the PERT signed a data user agreement.
Limitations of the Evaluation Design and Analyses
The evaluation design and subsequent analyses are not without limitations. Key limitations in the evaluation design and within each data collection approach and analysis strategy are addressed in their respective sections of this report.
Broader limitations that may make it difficult to draw inferences about the impact of the parity implementation are summarized below:
- The study design was quasi-experimental and did not include a randomized control group observed at the same points in time, making it difficult to interpret changes over time.
- A significant portion of the FEHB plans had State parity laws in varying stages of implementation. These regulations differed greatly in their requirements and location of beneficiary residence. The effect of variations in State parity laws represents a potential confound to the study. Even though State parity laws do not directly affect FEHB plan benefits (the FEHB parity policy supersedes State parity laws), insurers’ prior experiences with State parity laws may have influenced their approach to implementing the FEHB parity policy. The matched national non-FEHB comparison group diminished this threat considerably for the archival data, however. The effect of State parity laws may have also mitigated the impact of the FEHB parity implementation. Compared to nearly all State parity regulations, though, the FEHB parity policy is substantially broader.
- The selected plans were chosen purposively on the basis of various characteristics on which the plans were likely to differ. Thus, generalizations from these selected plans to all FEHB plans must be made cautiously.
- Only the archival claims and enrollment truly represent pre-parity data. Other data collection did not occur until after parity implementation (January 1, 2001).
- There is the possibility of adverse selection resulting from parity-related changes in benefits coverage across plans, complicating the estimation of the effect of parity on spending and use. This was partially addressed by comparing continually enrolled cohorts to all enrollees and by examining enrollment changes across the years.
- The evaluation included no data on beneficiaries’ experiences or unmet need for MH/SA treatment.
- The evaluation time frame captures only two years post-parity, and therefore does not address any longer term effects of MH/SA parity in the FEHB program.
"parity.pdf" (pdf, 5.07Mb)
"parityA.pdf" (pdf, 61.31Kb)
"parityB.pdf" (pdf, 194.85Kb)
"parityC.pdf" (pdf, 134.89Kb)