The rule of thumb is that signal-to-noise increases by the square root of the sample size. This is a brutal curve, and suggests that simply gathering more data

The rule of thumb is that signal-to-noise increases by the square root of the sample size. This is a brutal curve, and suggests that simply gathering more data is seldom practical. Another rule that I use myself is, "multiply p by 10." In other words, a p-value of 0.05 is as good as a coin toss. This sounds outrageous, but seems consistent with reality.