More Medicare Advantage plans nabbed top quality marks for their 2016 plans than last year, a sign that private insurers are trying to meet the federal government’s standards for high-quality products and coordinated healthcare for seniors.

But the CMS’ star ratings also showed that private Medicare plans are still failing on many levels, particularly when it comes to prescription drug benefits. Attaining four stars has clear marketing advantages, but the CMS has tied financial incentives to the rating system as well. Plans that earn at least four stars receive a 5% boost to their monthly per-member payments from Medicare, while those with lower scores receive nothing extra.