Depends on the definition of "work," of course, but overall the answer is "No," if by that one means that an investor using market timing strategies would regularly come out ahead of the buy-and-hold purchaser of stocks or mutual funds, a person who simply invests as soon as he or she has sufficient funds and leaves the shares invested for the long haul.
There are a few strategies that, at least for brief periods, have led investors to clear more profits for their short-term trades, yet these excess profits are generally slight and are sacrificed as soon as the higher taxes for short-term trading have been paid.
For example, a popular equity trading approach is to "Sell in May and go away," redeeming shares at the first market open in May (that is, just after 4/30) and buying back shares at the opening of the market on the first trading day following Halloween (just after October 31). Thus the sell in May investor remains out of the market for about 6 months a year. Historically, the period from May through October has been the half of the year that performs least well. Yet once low money market rates, short-term taxes, and anomalous years for the market are taken into account, one would do better to be a buy-and-hold stocks market investor.