*! version 1.0.0 23jul2018

raschify -- Transform 1PL model estimates to Rasch metric

Syntax

raschify

Description

raschify transforms 1PL model estimates to the Rasch metric.
All the postestimation tools available
after irt 1pl can be used with
the transformed results.

Examples

Setup

. webuse masc1

Fit a 1PL model to binary items q1-q9

. irt 1pl q1-q9

Transform the 1PL model coefficients to the Rasch metric

. raschify

Display parameters of the Rasch model

. irt

Use the Rasch model parameters to plot the ICCs

. irtgraph icc, blocation xlabel(,alt) legend(off)

Predict the latent trait

. predict ability, latent

Stored results

raschify changes the following results:

Macros

e(title) Rasch model

Matrices

e(b) coefficient vector, slope-intercept parameterization

e(V) variance-covariance matrix of the estimators

Authors

Rafal Raciborski

rraciborski@gmail.com