Benchmarking is, as I've written in the past, something of a moving target. Investment advisers, fund managers and yes, even newsletter writers seem to have myriad benchmarks against which they like to measure themselves or others. I've tried to be very consistent over the years, comparing performance for my Model Portfolios and Vanguard's funds to either 500 Index or, when it became available, Total Stock Market, as the kind of golden standard for performance.

But others like to mix and match. Now Vanguard is proposing that new benchmarks be created for measuring the performance of life-cycle funds like their Target Retirement funds. Why? Well, for one reason, no two life-cycle funds from different fund sponsors are exactly alike even if, for instance, they both have the year 2015 in their names. Vanguard's proposal, which they admit is a work in progress, is to have one benchmark that measures performance against the return needed to amass enough assets to have a successful retirement (which could mean dying with $1 left in your bank account, or something different) and a second that would measure returns against the fund manager's return expectations (which, of course, wouldn't be too onerous for Vanguard since its Target funds are primarily funds of index funds).

My favorite response, however, comes from John Prestbo, the man in charge of all of the Dow Jones Indexes and someone who knows something about index creation. He told Investment News that the problem is that fund companies want "a benchmark that mirrors their own mix, except not as good." I wish I'd said that.