Pulse Documentation

name: op-overlay-index-vs-baseline
kind: operator
category: OVERLAY
operator: OVERLAY_INDEX_VS_BASELINE
description: Per-point ratio index against a fixed positional baseline of an ordered SERIES host (×100).
type: reference
applies_to: process, compose
examples_tags: [overlay, time-series, comparison]

Overlays decorate the host; no Response.Components.

Use when

Each point of an ordered series as an index value against a chosen baseline point (point / baseline x 100), e.g. growth since launch.

Questions it answers:

• How have monthly sales grown relative to the launch month?
• How does each wave’s score compare with the first wave, scaled to 100?

Use something else:

• OVERLAY_DELTA_VS_BASELINE when you want the gap in the value’s own units.

Params

Scope must be group. Ref.BaselineIndex.Position (int, required) — >= 0; positional anchor in host order. Level/Within must be 0. Other Ref arms → PULSE_OVERLAY_REF_INCOMPATIBLE_WITH_SHAPE.

Host shape

SERIES — ordered grouped Process host (e.g. a date grouper). Ratio twin of the baseline delta.

Output

SERIES — one SeriesEntry per host group key in host order, carrying index = point / baseline × 100 on Summary.Statistic. Baseline ordinal itself emits 100.0 (self-vs-self). Layer Baseline = 100.

Gotchas

• Out-of-range Position → PULSE_OVERLAY_REF_UNKNOWN (predict + runtime via ResolveBaselineIndex).
• Zero baseline → NaN across entries + ONE PULSE_OVERLAY_REF_ZERO per layer, unlike the subtractive twin.
• Absent host point → SeriesEntry with unset Statistic.
• Absent baseline ordinal yields 0.0 from host → routes to zero-baseline arm.
• Buffered — host.ValueAt(Position) post-finalize via ApplyOverlaysSeries.
• Weighted host → weighted figure (reads the host payload).

See

• Skills: overlay-system, op-overlay-delta-vs-baseline, op-overlay-index-vs-prior.