FTB-C000019 / Formula component

Smoothing Constant

A smoothing constant controls how far an exponential state moves toward each new observation.

Also known asalphaEMA tracking rate

Definitions

In plain terms

A larger smoothing constant makes an EMA respond faster to new data, while a smaller value makes it change more slowly and remember older observations longer.

Technical

In EMA_t = EMA_(t-1) + alpha(z_t - EMA_(t-1)), alpha is a dimensionless value between zero and one that multiplies the current forecast error.

Scope

This concept describes the recurrence weight; it does not independently specify initialization, warm-up length, missing-data handling, or predictive value.

Examples

  • Alpha 0.10 closes 10 percent of the gap between the prior EMA and the current observation.

Common misconceptions

  • A 10 percent smoothing constant does not mean only the latest ten observations are used.

Concept relationships

Where this concept is used

Evidence and governance

  1. Calculating the McClellan Oscillator McClellan Financial Publications · first party methodology

    Supports: preferred label, short definition, technical definition, formula, units

    Limits: Does not prescribe one universal initialization, missing-session, revision-resolution, rounding, or software interface policy.

Reviewed by
fintech-builder-owner-approved
Last reviewed
2026-07-26
Next review
2027-07-26
Record status
published