A reader asks: Should I check my retirement accounts every day? Archer responds: Professional money managers like to obsess over something called “volatility.” By that they generally mean fluctuations in the prices of assets – stocks, bonds, etc. All kinds of tools have been created to measure the magnitude of those changes, the best known being Standard Deviation and the Sharpe Ratio, the brainchild of the Nobel Prize-winning William Sharpe. The former measures the range of variation from a mean, or average. The latter seeks to capture what is known as “risk-adjusted returns” through a process that involves a bunch of math. The relationship it purports to describe, as is generally the case with this kind of thing, is that of risk to reward.