Indicator Lag
The delay between a change in price and the corresponding change in an indicator derived from it.
Formula
Approximate lag of a simple moving average = (n - 1) / 2 periods, where n is the lookback
Unit
days
In depth
Lag is a mathematical consequence of averaging, not a defect: a mean of the last n values cannot reflect a turn until enough new values have entered the window to shift it. Every attempt to reduce lag — exponential weighting, shorter windows, adaptive periods — increases sensitivity to noise, and no construction escapes the trade-off. Understanding lag is what prevents the common complaint that an indicator signalled too late; it signalled exactly as its arithmetic requires. Indicators are therefore useful for confirming and for defining rules, not for anticipating.
Worked example
A 50-period simple moving average lags by roughly (50 - 1) / 2 = 24.5 periods. If price turns today, that average will not reflect the turn for about five trading weeks.
Illustrative figures, chosen so the arithmetic is easy to follow. Not a live price and not a valuation of any company.
Educational reference only
This entry explains what “Indicator Lag” means. It is not investment advice and not a recommendation to buy or sell any security. Any numbers above are illustrative, not live prices, and nothing here predicts price direction or rates a stock. Consider your own circumstances and consult a SEBI-registered investment adviser before acting.