Description: The paper demonstrates that the most popular rationalization for evolving glide paths is flawed and should be discarded. The paper also demonstrates that glide paths should generally evolve for investors that endeavor to optimize outcomes and reevaluate their portfolios regularly.

Description: Part one of a two-part article, to be contined in Feb 2014. Provides useful rules of thumb for breaking out investment return into components of periodic arithmetic return, geometric return, the volatility of returns and the correlation of returns by asset class. Develops and relates these axiomatic concepts into rules of thumb for estimating quantiles of a range of stochastic returns.