Only barely (see "What if we could perfectly time the market?" in [0] which cites [1]), and it is the height of self-delusion for anyone to think he or she will time it correctly, when professionals fail to do so. Don't try!
> Rather than putting it immediately into the market, he waited and invested after month-end January 1993—that year's monthly low point for the S&P 500. At the beginning of 1994, Peter received another $2,000. He waited and invested the money after March 1994, the monthly low point for the market for that year. He continued to time his investments perfectly every year through 2012.
That's hardly "perfectly timing the market" in the usual sense. I'd consider "perfectly timing" to be sell at every peak and buy at every trough, so you're always holding stocks when they're gaining versus the dollar and holding dollars when stocks are losing versus the dollar.
It's impractical, but it's a much better result -- the theoretical limit to how much you could have made with perfect knowledge of all the pricing ahead of time.
That analysis, by contrast, only looks at what happens if you have a little perfect information -- and the answer is "not much".