The answer: 10,000 fewer, according to one model designed by the researchers.

Now, the study is replete with caveats, estimates, assumptions, alternative outcomes, and so on. What the Yale team found was that very little prior research on MA plan mortality rates existed before they dug in. So these researchers had to find apples-to-apples plans to compare, sorting them by overall cost to the plan member, and digging through enough outcomes to deliver statistically significant trends.

But, with all the warnings out of the way, the study came to some fairly attention-grabbing conclusions:

1. Mortality rates vary widely by plan type within the same market. "This variation is a highly reliable predictor of true plan mortality effects with a novel quasi-experimental design," we are told.
2. Current plan ratings systems do not factor in mortality percentages. "Publicly available quality measures are uncorrelated with true mortality effects."
3. Consumers don't ask about mortality rates of plans when choosing a Medicare Advantage policy–mainly because they don't know they exist.
4. Even random reassignment of plan members from higher mortality to lower mortality plans would save lives. "One-year mortality would fall significantly if beneficiaries were reassigned to lower observational mortality plans, suggesting broad scope for policy interventions based on these measures."
5. Not only do some plans offer longer life, they offer seniors a better, longer life.
6. Generally speaking, the more expensive the MA plan, the lower the mortality rate.

"Our findings suggest large returns to understanding the market and plan-level determinants of plans' mortality effects. We find that plans with higher premiums, more generous drug coverage, and higher spending tend to reduce consumer mortality," the study found. "We find that randomly reassigning those in plans with the worst 5% observational mortality rates could avert around 10,000 elderly deaths each year. At conventional VSL estimates, such an effect would have a dollar-equivalent mortality benefit of $10,000 per reassigned enrollee."

But would consumers switch to lower mortality plans if they knew there were significant differences? This the researchers cannot say for certain. Because price is such a strong determinant in plan choice, even the promise of a longer (and better) fade into the sunset may not overcome the historic consumer resistance to plan cost.

That cost preference could be undercut if mortality rates were strongly publicized and consumers could understand that one "cost" of the cheaper plan was a shorter lifespan.

"From a policy perspective, our results suggest potentially large benefits from directing consumers to lower observational mortality plans. While the government does not currently release risk-adjusted mortality information, we find that such information might be incredibly important. Existing programs subsidize plans that score better on measures like star ratings, which we find to be uncorrelated with causal mortality effects. Such programs may therefore do a poor job of rewarding plans that improve beneficiary health and might do better if they targeted risk-adjusted mortality.

"Our results also imply that insurers face weak incentives to invest in improving consumer health, which could be strengthened by new contractual or organizational forms."