Testing changes · The measure · Element
The effect size
How much improvement would matter.
The part
What it is
Set before the test, since it determines how much traffic is needed and whether the test is worth running at all.
A change that could only plausibly produce a fractional improvement is a change not worth testing.
The smallest level
The attributes it carries
Each attribute is one of the framework’s shared types. What a date is, and how it is written, is defined once for the whole model — the note here says what it means in this particular place.