Health Care Cost Trends Request for Proposals - Impact of Recent ACA Enrollment Changes on Population Morbidity and Cost

Background and Purpose

The Affordable Care Act (ACA) individual market has experienced substantial changes in enrollment levels and composition over the past several years. Changes in premium assistance, eligibility and verification requirements, enrollment operations, state Marketplace structures, plan offerings, and consumer behavior have the potential to affect not only the number of covered lives but also the morbidity and expected cost of the insured population.

Recent experience provides a timely opportunity to examine these effects. The Centers for Medicare & Medicaid Services (CMS) reported 24.3 million Marketplace plan selections during the 2025 Open Enrollment Period and 23.1 million during the 2026 Open Enrollment Period, a decrease of approximately 5%. CMS also reported a meaningful shift in metal-level enrollment for 2026, with increased enrollment in Bronze and Gold plans and decreased enrollment in Silver plans. The COVID-related temporary enhanced premium tax credits expired at the end of 2025. During the same period, eligibility and program integrity actions, state subsidy programs, issuer and plan changes, and other operational developments affected coverage transitions and the comparability of results across years and states.

Open Enrollment Period plan selections do not necessarily represent effectuated or sustained coverage. Research under this RFP must distinguish plan selections from effectuation, retention, termination, and covered member-months. It must also distinguish observed associations from causal effects and identify the limits of attributing any outcome to a single policy or operational change.

Changes in affordability and enrollment processes may affect who enters, remains in, or exits the ACA individual market. These changes may produce selection effects that alter population morbidity, utilization patterns, claim costs, risk adjustment results, premium adequacy, and future rate development. Understanding the magnitude and drivers of these effects would be valuable to health actuaries, health plans, regulators, policymakers, and other stakeholders.

The Society of Actuaries (SOA) Research Institute, through the Health Care Cost Trends (HCCT) Strategic Research Committee, seeks an objective, data-driven assessment of how recent enrollment changes are associated with the morbidity and health care costs of the Marketplace and broader ACA-compliant individual market. The research should produce findings and monitoring methods that practicing health actuaries can apply to experience analysis, risk adjustment, and rate development.

Research Objective

The SOA is seeking proposals from researchers to evaluate the impact of recent ACA enrollment changes on population morbidity and health care cost. The study should focus primarily on recent Marketplace experience, including changes affecting plan years 2025 and 2026, while using earlier years as appropriate to establish baseline patterns and trends. Researchers may also incorporate emerging 2027 experience if it becomes available during the project.

The research should distinguish, where feasible, between changes attributable to enrollment selection or population mix and changes attributable to underlying medical trend, benefit design, geographic mix, provider prices, utilization intensity, or other factors. The selected researcher should clearly document the timing of relevant policy and operational changes and identify important limitations in attributing observed outcomes to any single change.

Examples of research questions that may be addressed include:

• How have Marketplace enrollment levels and the composition of the enrolled population changed, including by new versus returning enrollment, age, income, subsidy status, metal level, geography, and other relevant characteristics?
• To what extent are recent enrollment changes associated with measurable changes in morbidity, prospective or concurrent risk scores, prevalence of chronic conditions, utilization, allowed claims, or per-member-per-month costs?
• Are changes in morbidity or cost concentrated among particular market segments, states, demographic groups, subsidy populations, metal levels, or enrollment cohorts?
• How have changes in gross and net premiums, premium tax credit eligibility, plan choice, reenrollment, verification, or other enrollment processes affected retention, switching, entry, or exit from Marketplace coverage?
• Can observed changes in health care cost be decomposed into the effects of population selection, utilization, unit cost, benefit design, and other drivers?
• What are the implications of changes in population morbidity for ACA risk adjustment, issuer financial results, premium adequacy, rate development, and experience monitoring?
• What indicators or analytical framework could actuaries use to monitor future enrollment-driven changes in morbidity and cost as ACA policy and enrollment conditions continue to evolve?

The final report should be relevant to practicing health actuaries and should explain the data sources, methods, assumptions, limitations, and practical implications of the analysis. The SOA is especially interested in approaches that combine publicly available Marketplace information with claims, enrollment, risk score, rate filing, or other data where feasible. Proposals should identify any required proprietary data and describe the researcher's ability to obtain and use those data.

Proposal Requirements

Proposals should provide the following information:

1. Resumes of the researcher(s) indicating how their background, education and experience bear on their qualifications to undertake the research. If more than one researcher is involved, a single individual should be designated as the lead researcher and primary contact. The person submitting the proposal must be authorized to speak on behalf of all the researchers as well as for the firm or institution on whose behalf the proposal is submitted.
2. An outline of the approach to be used, including the proposed scope, relevant literature, data sources, methods, segmentation, and analytical techniques. The proposal should explain how the researcher would assess changes in population morbidity and cost; distinguish enrollment or selection effects from other cost drivers; address data limitations and potential confounding; and collaborate with the SOA and project oversight group to refine the research questions. Expected deliverables, including the final report and any supporting exhibits, models, data tables, or tools, should be described.
3. Cost estimates for the research, including data acquisition or licensing, analysis or modeling, report preparation, project management and any other related costs. Such estimates can be in the form of hourly rates, but in such cases, time estimates should also be included. Any guarantees as to total cost should be given and will be considered in the evaluation of the proposal. While cost will be a factor in the evaluation of the proposal, it will not necessarily be the decisive factor.
4. A schedule for completion of the research, identifying key dates or time frames for delivery of preliminary results and reports.
5. Suggestions in the proposal for ensuring timely delivery, such as fee adjustments, are encouraged.
6. Other related factors that give evidence of a proposer's capabilities to perform in a superior fashion should be detailed, especially prior experience with ACA Marketplace or individual market research, health insurance claims and enrollment data, morbidity or risk adjustment analysis, health care cost research, or actuarial audiences.
7. Proposals should be limited to 5 pages (excluding the resumes of researchers).

Proposals should be submitted to Research-HCCT@soa.org by the end of the day on October 30, 2026. Expressions of interest should be submitted by October 12, 2026. Proposals that are accompanied by an expression of interest will be given additional consideration. Decisions on whether a proposal is chosen will be communicated by November 30, 2026.

Selection Process

The HCCT Strategic Research Committee will appoint a project oversight group (POG) to oversee the project. The POG is responsible for recommending the proposal to be funded. Input from other knowledgeable individuals also may be sought, but the HCCT will make the final recommendation, subject to Society of Actuaries Research Institute leadership approval. An SOA staff research actuary will provide staff actuarial support.

Questions

Any questions regarding this RFP should be directed to Research-HCCT@soa.org.

Conditions

The selection of a proposal is conditioned upon and not considered final until a Letter of Agreement is executed by both the Society of Actuaries Research Institute and the researcher.

The Society of Actuaries Research Institute reserves the right to not award a contract for this research. Reasons for not awarding a contract could include, but are not limited to, a lack of acceptable proposals or a finding that insufficient funds are available. The Society of Actuaries Research Institute also reserves the right to redirect the project as is deemed advisable.

The Society of Actuaries Research Institute plans to hold the copyright to the research and to publish the results with appropriate credit given to the researcher(s).

The Society of Actuaries Research Institute may choose to seek public exposure or media attention for this research. By submitting a proposal, you agree to cooperate with the Society of Actuaries in publicizing or promoting the research and responding to media requests.

The Society of Actuaries Research Institute may also choose to market and promote the research to members, candidates and other interested parties. You agree to perform promotional communication requested by the Society of Actuaries Research Institute, which may include, but is not limited to, leading a webcast on the research, presenting the research at an SOA meeting, and/or writing an article on the research for an SOA newsletter.

Conflict of Interest

Proposers must disclose material business, financial and organizational interests and affiliations which are or may be construed to be reasonably related to the interest, activities and programs of the Society of Actuaries Research Institute. The selected researcher must update the disclosure if a relevant interest arises during the project.

Appendix

The cost ranges below are intended as a guide for budgeting project costs for proposals in response to SOA Research Institute Request for Proposals (RFP). Please note these figures span the 33rd to 66th percentiles for all projects as well as projects that involve a specific approach (lit review, survey, etc.). They are based on historical costs over several recent years. Expected costs for some RFPs may fall outside these ranges depending on the nature of the work and resources required for completion.

All Contracted Projects

This category includes all contracted projects that the Institute has undertaken within the last several years.

The 33rd-66th percentile project costs range is $25,000 - $50,000.

Literature Reviews

This category includes projects that involved only a literature review or the cost for the portion of a larger project that included a literature review.

The 33rd-66th percentile project costs range is $15,000 - $20,000.

Surveys

This category includes all projects that had a survey as their primary component.

The 33rd-66th percentile project costs range is $28,000 - $55,000.