One of the commenters offered a retort that I've seen in a bunch of places: "Of course Medicare is growing faster! It cares for a sicker population!"
It's a common intuition, but it's wrong. Consider a simple model of a population with two groups: young and old. Assume that the old consume five times as much of an undifferentiated good, healthcare, as the young do, and that each unit costs $2,000. So the oung cost us $2,000 apiece per year, and the old cost us $10K. Now assume that the cost of healthcare in each group grows at 10% a year. At the end of five years, each young person will cost us $3,221 and each old person will cost us $16,105 - or exactly five times as much as a young person.
First of all, Megan reminds us yet again that there's no good reason to look up facts when you can just make up a hypothetical. Eight seconds of Google research would have shown that her entire premise is made of stupid and wrong.
Second, the CBO report on which she bases her entire argument that Medicare/Medicaid are growing faster than private insurance explicitly says that it shouldn't be used to say Medicare/Medicaid are growing faster then private insurance. Megan, you so bad! The sign says "No Loitering" but you loiter anyway!
Third, look at the fucking math she feels compelled to show us. "Assume" that the old consume five times as much healthcare as the young. If each grows by 10%, after five years the old will consume five times as much healthcare as the young. Watch Megan's neurons fire wildly in an effort to understand multiplication. In other news, if Megan is twice as stupid as Jonah Goldberg and they each double their stupid over the next year, Megan will be twice as stupid as Jonah Goldberg.
Fourth, way to pull a McArdletm by throwing in a $5 phrase like "an undifferentiated good" in an effort to sound smart and cover up the fact that she hasn't the slightest idea what in holy hell she's talking about.
Fifth, stay tuned for the Oscar-baiting biopic of Megan McArdle starring Tara Reid as a dull young girl who overcomes her childhood addiction to eating Elmer's glue and her own shit to become a Real Financial Journalist.
In conclusion, if we assume that the elderly use far more healthcare than the young and that their use increases at a faster rate, we can clearly see that the elderly use far more healthcare than the young and that their use increases at a faster rate.