Sensitivity

Write down the smallest real change your measure can actually see, given sample size and normal noise. Other slots say what you count; this one says how fine a difference counting can resolve before the result is unreadable.

Write down the smallest real change your measure can actually see, given sample size and normal noise. Other slots say what you count; this one says how fine a difference counting can resolve before the result is unreadable.

Example

On the activation card: 4,000 signups a month, and day-seven logins bounce about 2 points week to week with nothing changed. So you write: cannot detect shifts under 3 points. The claimed 18 percent lift clears that floor; a 2 point one would not.