SNSequate

Contains functions to perform various models and methods for test equating (Kolen and Brennan, 2014 doi:10.1007/978-1-4939-0317-7 ; Gonzalez and Wiberg, 2017 doi:10.1007/978-3-319-51824-4 ; von Davier et. al, 2004 doi:10.1007/b97446). It currently implements the traditional mean, linear and equipercentile equating methods. Both IRT observed-score and true-score equating are also supported, as well as the mean-mean, mean-sigma, Haebara and Stocking-Lord IRT linking methods. It also supports newest methods such that local equating, kernel equating (using Gaussian, logistic, Epanechnikov, uniform and adaptive kernels) with presmoothing, and IRT parameter linking methods based on asymmetric item characteristic functions. Functions to obtain both standard error of equating (SEE) and standard error of equating differences between two equating functions (SEED) are also implemented for the kernel method of equating.