Skip to main content

Δ-B

Jason Hreha· Updated August 9, 2026

Definition. Δ-B is the change in the target behavior rate after an intervention, reported in percentage points with the baseline, denominator, and measurement window.

Reporting standard #

Always report:

  • Baseline rate, post rate, and Δ-B in percentage points.
  • Relative change in percent for context.
  • Sample size, assignment method, and denominator.
  • Measurement window and data source.
  • Segment by the limiting BSM component if known.

Formulas #

  • Δ-B (pp) = Post% − Baseline%
  • Relative change (%) = (Post% − Baseline%) / Baseline% × 100

Examples #

These calculations are illustrative, not observed results.

  • Example 1: Baseline 20% complete the behavior; post 30% do. Δ-B = +10 pp. Relative change = +50%.
  • Example 2: Baseline 5% to post 7%. Δ-B = +2 pp. Relative change = +40%. Report n and the observation window with every relative change.

Counterexample: A proxy metric (e.g., page views) increased, but the target behavior (e.g., task completion) did not change. Report Δ-B for the target behavior, not the proxy.

Add a claim to the Evidence Ledger when you report Δ-B.

See also