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2024 Star Ratings Turmoil Creates Huge Vulnerability for Medicare Advantage Plans

While the Medicare Advantage (MA) Star Program has always made it difficult for plans to achieve and maintain high Star scores, the Star roller coaster ride has been much more profound over the past several years.  We now have had two years of pretty bad news, which puts a blemish on the program (fair or not). What’s more, the percentage of high-scoring contracts and the percentage of enrollment in them are now below pre-COVID years. 

To refresh a bit on this, during the COVID pandemic, the Centers for Medicare and Medicaid Services (CMS) created fairly major calculation allowances for both Star 2021 (2019 and 2020 data) and 2022 (2020 and 2021 data). These allowances had the effect of boosting Star scores. We saw a surge in Star scores in 2022, including for plans that historically did not have a great track record of consistently hitting 4 Stars and above.  However, for 2023 Star measurement, almost all of the COVID calculation allowances were lifted and we saw a huge drop in Star achievement.  In Star 2024, more drops and volatility occurred because calculations saw some major changes and far-more-complex measures were added.

Let’s dive deep here by looking at global metrics:

 Average MA-PD scoreContracts with 4-Star or greaterEnrollment in plans with 4-Star or greater5-Star Contracts
2021 (COVID impact; some COVID allowances)4.0648.5%76.8%21
2022 (COVID impact; some COVID allowances)4.3768.4%89.7%74
2023 (COVID impact; COVID allowances removed except 3 HOS measures)4.1451.3%72.1%57
2024 (little COVID impact; no COVID allowances; new measures; no weighting; Tukey outlier implemented4.0442.0%73.7%31

If you look at the pre-COVID base year of 2021, the 2024 post-COVID results are about the same in terms of average Star score (4.06 to 4.04).  The number of rated contracts with 4-Star or greater did drop from 48.5% to 42.0%. Enrollment in 4-Star or greater plans also dropped from 76.8% to 73.7%.  The drops noted are not terribly significant, but are worrisome.  Overall, the quality in the program is roughly the same or has dropped a bit. But it shows that the 2022 surge was very much artificial and driven by the COVID allowances.

The lower scores in 2024 from 2023 are very much tied to the following:

  • Three new measures in 2024 that are tough and complex
  • Recent changes in weighting of certain scores in 2023 and 2024, notably survey measures
  • The addition of the Tukey outliers deletion in 2024 (5% guardrails were also introduced in 2023).

All of the above will continue to impact plans moving forward and there will be the additional complication of electronic measures submission that will replace manual chart chasing over time. As well, for those contracts with high penetration of dual eligibles, certain Low Income Subsidy (LIS) eligibles, and disabled enrollees, there are complaints that the Categorical Adjustment Index (CAI) is not living up to expectations.

What Is Tukey?

We are close to Thanksgiving, so some of you may be asking “What is Tukey?”  It is the removal of outlier performance at the top and bottom of the contract rankings for certain measures.  After the removal of outlier performance of certain contracts (high and low), then the mean resampling, hierarchical clustering, guardrails (movement of cut points no more than 5% upward or downward), and other factors are applied, as applicable, to determine cut points for each Star measure.  Note that because of the introduction of Tukey in Star 2024, the 2023 Star was simulated with Tukey to take into account the 5% guardrails.

What was the effect of the Tukey introduction? Suzanna-Grace Tritt of Wakely explains this in two white papers ( ) and ( ).  She explains that there are often more low-performing outliers than high-performing ones. By removing the low outliers, Tukey had the effect of increasing cut points for 2024 Star Ratings throughout the 1 to 5 range. She notes that far more cut points have increased than decreased. In essence it made it harder for all contracts to improve or maintain their Star Rating overall by depressing measure scoring.  Removing the outliers made it tougher by pushing most cut points higher. This goes for both high- and low-scoring plans. Think of it as walking up stairs but suddenly the height of each step gets larger. It is hard for you to step up and you are bound to stumble — as many plans did.

Suzanna-Grace notes that Tukey (along with guardrails) will reduce cut point change variability in the future, but it does have a major adjustment impact by increasing cut points from 2023 to 2024. Wakely calculated the Tukey impact as a decline of 0.2 for the aggregate score in 2024. Wakely found that Tukey had the largest impact on 5 Star contracts, moving over 20 contracts from 5 to 4.5 Stars.

What is interesting, though, is that there is clear positive progress from the 2023 Tukey simulation to actual 2024 scores. Except for the 5 Star category, every category from 3 and above (0.5 increments) had more contracts than the 2023 Tukey simulation.  That is the hidden good news and is something plans can embrace in a year of bad press.

Overall News Not Good

But overall, the news was not good.  As can be seen from the aggregate statistics for all contracts from 2023 and 2024, Tukey, weighting, and new measures largely pushed down high performers.  The number of bonus-qualifying contracts will be 229 in 2024 compared with 260 in 2023. The 5 Star contracts took losses to 4.5 and below. Many contracts also dropped from 4 to 3.5 or less. But it is important to remember that the weighted enrollment from 2023 to 2024 is actually going up. Consumers have become very savvy and are searching for the best plan for them – both in terms of quality outcomes and the most additional benefits (the level of additional benefits is driven by Star performance).

Star Score2023 Contracts2024 Contracts

Dwight Pattison adds to this with a deep analysis looking at each 2023 rated contract and what happened to it in 2024. Here are his findings:

2023 Star Level2024 Drop Percentage2024 Stayed The Same Percentage2024 Improved Percentage
5 or 4.555%41%4%
4 or 3.540%41%19%
3, 2.5 or 213%44%43%

So Dwight found that over one-third (37%) of plans lost Star power in 2024. While Wakely noted that the removal of the outliers moved many cut points up and affected all levels of Star performance, Dwight notes that the biggest impact was felt at the higher end of performance.  About 55% of 4.5 and 5 lost Star power, with 40% of 4 or 3.5 plans losing Star power.

Remember that the 2025 payment year is impacted by 2024 Star.  You must have a 4 Star to get your 5% quality bonus factored in.  As for the rate rebate, 4.5 and 5 Star plans get to keep 70% of the difference between their Medicare basic benefit bid and the country benchmark with bonus. 3.5- and 4 Star plans keep 65%.  Thus, some plans will lose not only their quality bonus but their greater share of the rate rebate.

Additional Statistics From The Star Fact Sheet

  • There are 42 Medicare Advantage-Part D measures — 30 Part C and 12 Part D.
    • In terms of Part C measures, from 2023 to 2024, 5 measures increased, 7 stayed the same and 15 dropped.  The remaining three were new measures, which registered relatively low scores as well: Plan All-Cause Readmissions (2.9), Transition of Care (2.5), and Follow-up after Emergency Department Visit for People with Multiple High-Risk Chronic Conditions.
    • In terms of Part D measures, 5 measures increased, 2 stayed the same and 5 dropped.
  • As usual, not-for-profit plans tended to score better than for-profit ones. Approximately 56% of non-profit contracts received 4 or more stars compared to 36% of for-profit MA-PDs.
  • As well, tenure plays a big part in Star achievement. MA-PDs with 10 or more years in the program are more likely to have 4 or more stars compared to contracts with less than 5 years in the program.


The 2023 and 2024 Star scores announcement showed that plans big and small can be taken by surprise and have trouble achieving and maintaining high scores. Wakely says small to medium plans were disproportionately impacted by Tukey’s adoption and that small plans have materially lower performance than medium, high, and mega plans.

But big players also struggle. United and Humana seem to have locked in good scores over time, although even they have had some volatility of late. Other large national players have had trouble in 2023 and/or 2024. Some big players bounced back in 2024, while others continued to show poor performance. Still others dropped in 2024 after having a relatively good 2023.

In some ways, the COVID allowances have led many plans to be complacent in a key revenue and competitive advantage area. Many plans lack the technology, clean and timely data, and expertise to hone a consistent and high-performing program. This is leading to plans reporting major revenue losses for 2024 (from 2023 Stars) and 2025 (from 2024 Star).

What many plans fail to appreciate is the “long tail” of Star.  What do I mean?  The 42 measures for MA-PD plans are a curious concoction of clinical, survey, and plan performance measures. Data used to calculate a given Star year may be one year back for CAHPS and two years back for HOS surveys, clinical measures, and plan performance metrics. Within the HEDIS clinical measures, the lookback for compliancy can add one or more years as well. Once you get a Star score, it does not impact your revenue until the next year.  So what you did a year ago and do today impacts your Star score and revenue well into the future. What’s more, plans have to be working multiple Star years at once due to this lag. The point is that MA plans can never lose focus on the program or they risk huge fallout well into the future.


I wanted to extend a thank you to the following for their expertise and analysis on the very complicated subject of Stars.  Both of them have posted insights on Star 2024 over the past few weeks.  Their business or LinkedIn links are here for you to go to for some of their great source material.

Suzanna-Grace Tritt of Wakely —

Dwight Pattison of Quality Performance Advantage —

#stars #medicareadvantage #quality

3/4/2024 Update: Although details are not known, Elevance Health got the Centers for Medicare and Medicaid Services (CMS) to relook at and boost the plan’s Star scores for 2024.  Elevance had filed a lawsuit against CMS after its scores were announced in October. Elevance will see a boost of $190 million.  Four of its contract scores were revised. Elevance says 49% of its Medicare Advantage (MA) members now will be enrolled in plans rated 4 Star or greater, up from 34%.

— Marc S. Ryan

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