Pychometrik

Product or Programme · All products and programmes
Evidence · 5 claims (5 for) · 1 study (1 design), q2 · 0 of 1 report an effect size · 5 claims rest on one study

Description

Pychometrik is a Python-based item-analysis and Rasch item-calibration tool developed by NWEA for psychometricians calibrating assessment items.

Components

Claims

• When item difficulty and simulee ability ranges align (minimum -10, maximum 8), Pychometrik recovery is accurate, with correlations above 0.99 across all three sample sizes; recovery degrades above the simulee ability maximum of 7.94 [+W]
• Item calibration results from Pychometrik and the existing tool are mostly comparable across 1,180 AGC-calibrated MAP Growth items, with average RIT differences ranging from 0.33 (mathematics) to 0.91 (science) [+W]
• Log-likelihood comparisons indicate Pychometrik can produce more accurate item parameter estimates than the existing tool for items with RIT differences larger than 2 [+W]
• In the Pychometrik item parameter recovery simulation across 27 conditions (Grades K-8, sample sizes 500, 1,000, and 2,000), recovery accuracy increased with sample size and was best for Grade 8 simulees [+W]
• In a fixed-person calibration simulation with 60 Rasch items and 1,200 simulees, estimates from both tools were comparable to true parameters, with the existing tool underestimating difficulty by 0.03 RIT on average [+W]

Related Products and Programmes

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Key Sources

• He, W., Bo, E., Meyer, P., & Grandgeorge, R. (2021). A comparison of item parameter estimates in Pychometrik and the existing item calibration tool. NWEA. https://www.nwea.org/research/publication/a-comparison-of-item-parameter-estimates-in-pychometrik-and-the-existing-item-calibration-tool/

Page metadata

Field	Value
type	product
id	pychometrik
title	Pychometrik
description	Pychometrik is a Python-based item-analysis and Rasch item-calibration tool developed by NWEA for psychometricians calibrating assessment items.
status	review
moved_from	element/pychometrik-item-calibration-tool
product_kind	software
generated	by process:sweep-kinds on 2026-10-10
trust	unverified — no one has confirmed this page's content
sources	1 — he-2021

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