# estimation

## Scaling and Standard Errors in SEM

In this post, I demonstrate why rescaling a coefficient (i.e., multiplied/divided by a constant) is different from “standardizing” a coefficient (i.e., multiplied/divided by the sample standard deviation, which is a random variable) in SEM.

## Estimating a 2-PL Model in Julia (Part 2)

E-Step M-Step Estimating a 2-PL Model with EM in Julia Find $$\bar r_{jk}$$ and $$\bar n_k$$ Solve estimating equations Iterations Stopping criteria Benchmarking Remark $\newcommand{\bv}[1]{\boldsymbol{\mathbf{#1}}}$

## Estimating a 2-PL Model in Julia (Part 1)

Import Data Two-Parameter Logistic Model Estimation with mirt in R Marginal Maximum Likelihood (MML) Estimation Implement MML Estimation in Julia Import R data Compute marginal loglikelihood Optimization Benchmarking The semester is finally over, and for some reason, I wanted to consolidate my understanding of some psychometric models, perhaps because I’ll be teaching a graduate measurement class soon.