Indicator period
The number of intervals over which an indicator computes its value.
How to read the number
The period is a trade: a short one reacts faster and jitters more, a long one is smoother and lags more. No choice of number improves both properties at once.
When the metric lies
Selecting the period on past data almost always improves the picture on that same history and says almost nothing about the stretch that follows.
Also known as: lookback period