Contract-level enrollment forecast for plan year 2027, gated by a 2024 backtest. Prophet where history is long enough; seasonal-naive where it is not; a flat extrapolation for the small remainder of contracts with sparse history.
Median Prophet MAPE was 6.20% on the 2024 holdout backtest; the seasonal-naive baseline came in at 18.34%. Forecasts publish only when the chosen method beats the baseline on its own contract history — otherwise the contract falls back to seasonal-naive or, where even that is unsupported, to a flat extrapolation at the last observation.
Short history; last-year repeat with monthly seasonal shape.
Long history; additive trend + yearly seasonality.
Too few months to fit; flat extrapolation at the last observation.
| # | Contract | Parent organization | May 2026 | Jan 2027 | Δ | Method |
|---|---|---|---|---|---|---|
| 01 | H3811 | Samaritan Health Services, Inc. | 1.4K | 12K | +739.3% | Prophet |
| 02 | H5965 | Centene Corporation | 1.3K | 9.7K | +620.1% | Prophet |
| 03 | H5042 | Lifetime Healthcare, Inc. | 3.6K | 12.9K | +263.5% | Prophet |
| 04 | H7849 | Health Care Service Corporation | 24.7K | 83.9K | +239.8% | Prophet |
| 05 | H3557 | Blue Cross & Blue Shield of Rhode Island | 2.1K | 6.8K | +226.7% | Prophet |
| 06 | H6202 | Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 6.3K | 20.3K | +222.4% | Prophet |
| 07 | H5989 | Healthfirst, Inc. | 14.1K | 41.2K | +192.5% | Prophet |
| 08 | H7323 | Centene Corporation | 2K | 5.9K | +188.1% | Prophet |
| 09 | H8597 | CVS Health Corporation | 14.6K | 31.8K | +118.6% | Prophet |
| 10 | H3192 | CVS Health Corporation | 27.1K | 55.3K | +103.8% | Prophet |
| 11 | H3909 | Independence Health Group, Inc. | 22.1K | 43.6K | +97.3% | Prophet |
| 12 | H1610 | CVS Health Corporation | 11.5K | 20.4K | +77.7% | Prophet |
| # | Contract | Parent organization | May 2026 | Jan 2027 | Δ | Method |
|---|---|---|---|---|---|---|
| 01 | H3748 | CVS Health Corporation | 4.4K | 0 | −100.0% | Prophet |
| 02 | H5991 | EmblemHealth, Inc. | 2.3K | 0 | −100.0% | Prophet |
| 03 | H5435 | UnitedHealth Group, Inc. | 1.4K | 442 | −68.2% | Prophet |
| 04 | H3288 | CVS Health Corporation | 66.2K | 24.4K | −63.2% | Prophet |
| 05 | H6154 | Medica Holding Company | 1.8K | 813 | −53.6% | Prophet |
| 06 | H6910 | Trinity Health Corporation | 21.9K | 10.3K | −53.0% | Prophet |
| 07 | H1894 | Elevance Health, Inc. | 2.2K | 1K | −53.0% | Prophet |
| 08 | H5793 | CVS Health Corporation | 20.4K | 10.5K | −48.7% | Prophet |
| 09 | H2261 | Blue Cross and Blue Shield of Massachusetts, Inc. | 41.5K | 22.2K | −46.6% | Prophet |
| 10 | H3810 | AllCare Health, Inc. | 2.5K | 1.3K | −45.4% | Prophet |
| 11 | H1862 | Centene Corporation | 13.1K | 7.3K | −44.5% | Prophet |
| 12 | H2491 | Centene Corporation | 10.1K | 5.8K | −42.7% | Prophet |