Pulse Documentation

name: op-attr-tscore
description: Per-row T-score column — z-score rescaled to mean 50, stddev 10.
kind: operator
category: ATTR
operator: ATTR_TSCORE
type: reference
applies_to: process, compose, predict
examples_tags: [distribution-shape, buffered-pipeline]

Attributes emit row-level scalars; they do not produce Response.Components.

Use when

Adds to every row its T-score: the z-score rescaled so the mean is 50 and one standard deviation is 10.

Questions it answers:

• How does each candidate’s test result compare with the group, on a 50-centred scale?
• Which respondents score more than one standard deviation above average?

Use something else:

• ATTR_ZSCORE when you want plain standard-deviation units centred on 0.

Params

None. Weight (both kinds, same scores; "weight": null opts out): weighted mean and population sd √(Σw(x − μ)²/Σw); a zero / invalid-weight row adds no mass but is still scored.

Inputs

Output

One float64 per record — 50 + 10 * zscore. Null source → 50 (not null).

Reading the output

• value: The z-score rescaled to a mean of 50 and a standard deviation of 10: 50 + 10 * z, with the population standard deviation (dividing by n). 60 is one standard deviation above the mean, 40 one below.
  • Caveat: Unrelated to Student’s t or a t test: the name comes from educational testing, and the value carries no p-value.
  • Caveat: It is not a percentile: 70 does not mean the 70th percentile. Only on a roughly normal field does 60 sit near the 84th percentile.

Gotchas

• Two-pass: a Welford pre-pass computes the mean and sd. Reading-friendly scale for survey / education contexts (mean 50, sd 10, no negatives in the typical range).
• Zero stddev → 50 per row.
• decimal128 rejected.
• Not a percentile — same shape as the underlying distribution.
• set_* rejected at build time with PROCESSING_CONFIG — a bitmask has no value to standardise.

See

• pulse_examples_search tags=[distribution-shape]
• Skills: attribute-composition, op-attr-zscore, op-attr-normalized