als-statistics/goldens/tests/realiability.js

Modular JS statistics toolkit for Node.js and the browser: descriptive stats, correlations (Pearson/Spearman/Kendall), t-tests & ANOVA (Student/Welch), reliability (Cronbach’s alpha), regression (linear/logistic), clustering (DBSCAN/HDBSCAN), and table/co

import { EPS } from "../settings.js";
import { Analyze } from "../../lib/index.js";
const { Correlate } = Analyze;
const { CronbachAlpha } = Correlate; // exported class

import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { nearlyEqual, hasDataOrSkip, splitGroups, toRecordFromArray } from '../helpers.js'

export function testReliability(g) {
   const { X, Y, group, score, before, after, Q1, Q2, Q3, Q4 } = g.data;

   describe('Reliability (Cronbach’s alpha)', () => {
      it('alpha and alpha-if-deleted', () => {
         const items = { Q1, Q2, Q3, Q4 };
         const alpha = new CronbachAlpha(items);
         nearlyEqual(alpha.alpha, g.reliability.cronbach_alpha, 5e-6, 'alpha');
   
         // Normalize shapes: library may expose array of [name, value] or an object; compare per-item
         const libMap = Array.isArray(alpha.ifItemsDeleted)
            ? Object.fromEntries(alpha.ifItemsDeleted)
            : alpha.ifItemsDeleted;
   
         for (const [k, v] of Object.entries(g.reliability.if_items_deleted)) {
            assert.ok(k in libMap, `missing alpha-if-deleted for ${k}`);
            nearlyEqual(libMap[k], v, 1e-5, `alpha_if_deleted ${k}`);
         }
      });
   });
}