That's the gold standard, there's no question, but for any drug, there is going to be someone who is a super responder and there might be someone who doesn't respond at all. Sometimes you have to try a few before you hit the magic sauce, so you want to have options for people. That's where the choice and the options, we feel, are important.
Also, for a lot of the very new and expensive drugs, the evidence is very unclear. Clinical trials that have been done may not have been great and it's not obvious whether the drug will be effective or not, so reasonable people land in different places as a result. If you had 10 drug plan managers at the table with us, they would all say that they have an evidence-based formulary, and they've all landed in slightly different places with what they cover. It's not the case that there's this one absolute answer to these things. We think choice and some variability are important.