Changes in version 2.2.0 (2026-03-17) - Discretized response analysis is partially supported; dr1 assumes equal intervals and estimates the slope, intercept, and precision parameters, and dr2 uses fixed slope and intercept parameters and estimates the category intervals. Changes in version 2.1.0 (2024-10-04) - Weighted likelihood estimates (WLE) are available for ability parameter estimation. - adaptive_test function is added for ability parameter estimation with fixed item parameters. - IRTest_Cont utilizes MLE in item parameter estimation for a faster estimation. Changes in version 2.0.0 (2024-03-22) - IRT analysis for continuous item responses is now available. - IRTest_Cont has been added. - Other utility functions of IRTest are applicable to an output of IRTest_Cont. Changes in version 1.12.1 - Modified estimation functions to be utilized in ability estimation of adaptive testing. Changes in version 1.12.0 (2023-10-16) - Developed functions for medel comparison and model selection. - Modified GHc as an implicit object. - Provided examples for functions. - Changed from any(class()) to inherits(). - Provided more S3 methods. - Updated the manual. - Added coef_se that returns S.E. of item parameter estimates. Changes in version 1.11.0 (2023-09-19) - Graded response model ("GRM") is now available. - Developed MLE for mixed-format analysis. Changes in version 1.10.0 - Outputs reflect item names in an input file. - Enhanced algorithm convergence for IRTest_Dich when there exist one or more negative slope parameters. - Error in calculating MLE in the presence of missing data is resolved. - summary returns the HQ criterion. - Error in DataGeneration's model_D argument is fixed. - plot function employs latent_distribution. Changes in version 1.9.1 - Minor errors have been corrected such as the calculation of $\rho_{\theta\theta^{'}}$ with discrete latent distribution and the calculation of $sd$ in the Davidian-cure method. - Vignette file has been updated. Changes in version 1.9.0 - latent_distribution has been developed. This function evaluates an estimated latent density function. - reliability calculates a coefficient on the $\theta$ scale. Changes in version 1.8.1 - Convergence of the estimation algorithm was enhanced for "PCM" by inserting latest item parameters instead of inserting starting values repeatedly. Changes in version 1.8.0 - inform_f_item and inform_f_test are developed. - Convergence for "DC" and "LLS" was enhanced by updating density parameters every iteration. Changes in version 1.7.1 - Minor errors in the manual file are corrected. - reliability uses the raw value in a given data for calculating the reliability coefficient. - reliability returns both test reliability coefficient and item reliability coefficients. - Every estimation function returns the raw score-categories of items. Changes in version 1.7.0 (2023-08-17) - Log-linear smoothing method (latent_dist = "LLS") can be applied to estimate a latent distribution. Changes in version 1.6.0 - reliability has been developed to calculate marginal reliability coefficient of IRT. Changes in version 1.5.2 - Some of the polytomous items could be technically dichotomous when one or more of the categories are not observed in data. Now, these items can be analyised with the polytomous function. Changes in version 1.5.1 - Rasch-type analysis imposes a constraint on slope parameters to be equal across all items. Before, they were fixed to 1 regardless of the characteristics of data. Changes in version 1.5.0 - plot_item has been developed to draw an item response function. Changes in version 1.4.1 - Enhanced algorithm convergence for IRTest_Poly when there exist one or more negative slope parameters. Changes in version 1.4.0 - item_fit evaluates item fit. Changes in version 1.3.1 - Starting values (initialitem) can be automatically generated. Changes in version 1.3.0 - NA values are permitted for estimation functions. Changes in version 1.2.0 - The MLE option for ability parameter estimation is added for polytomous data. Changes in version 1.1.0 - The PCM model for polytomous data is available. Changes in version 1.0.0 (2023-07-18) - Unit tests are more thoroughly conducted to enhance 'test coverage.' - S3 class generic functions (i.e., print, plot, summary) can now be used for IRTest results. - Plotting function "plot_LD" is substituted with the generic function plot. - Additional ggplot2 arguments can be specified to plot. - Badges are added to the Github main page in order for the current status of IRTest to be easily recognized. - In the summary, additional information is provided; a cursory view of the latent distribution, model fit indices, and the number of parameters used. Changes in version 0.1.0 (2023-04-02) - Ability parameter MLE is available for IRTest_Dich. - Data Generation with fixed item and/or ability parameters is available. Changes in version 0.0.2 (2022-09-06) - Re-submission to CRAN. Changes in version 0.0.1 - The initial release.