similar to: New R package plink for separate calibration IRT linking

An updated version of the package plink has been uploaded to CRAN. This is a major revision that now includes multidimensional models and methods. plink is a package for conducting unidimensional and multidimensional IRT-based test linking using separate calibration methods for multiple groups for single-format or mixed-format common items. The package supports sixteen IRT models and eleven

An updated version of the package plink has been uploaded to CRAN. This is a major revision that now includes multidimensional models and methods. plink is a package for conducting unidimensional and multidimensional IRT-based test linking using separate calibration methods for multiple groups for single-format or mixed-format common items. The package supports sixteen IRT models and eleven

I have the following item response theory (IRT) likelihood that I want to maximize w.r.t. to theta (student ability). L(\theta) = \prod(p(x)) Where p(x) is the 3-parameter logistic model when items are scored dichotomously (x_{ij} = 0 or 1) and p(x) is Muraki's generalized partial credit model when items are scored polytomously (x_{ij} = 0 \ldots J). Now, I wrote the following two functions

Dear R-users, I'd like to announce the release of the new version of package 'ltm' (i.e., ltm_0.9-0 soon available from CRAN) for Item Response Theory analyses. This package provides a flexible framework for analyzing dichotomous and polytomous data under various IRT models. Furthermore, supporting functions for descriptive statistics, goodness-of-fit, ability estimation and

Dear R-users, I'd like to announce the release of the new version of package 'ltm' (i.e., ltm_0.9-0 soon available from CRAN) for Item Response Theory analyses. This package provides a flexible framework for analyzing dichotomous and polytomous data under various IRT models. Furthermore, supporting functions for descriptive statistics, goodness-of-fit, ability estimation and

Version 1.1 of the MiscPsycho package had been uploaded to CRAN. The package has been updated to include the following: 1) The irt.ability() function that estimates examinee ability given a set of item parameters. The function is very general and can be used to estimate ability when there are only dichotomous items (1-, 2-, or 3PL), only polytomous items (generalized partial credit model), or a

Version 1.1 of the MiscPsycho package had been uploaded to CRAN. The package has been updated to include the following: 1) The irt.ability() function that estimates examinee ability given a set of item parameters. The function is very general and can be used to estimate ability when there are only dichotomous items (1-, 2-, or 3PL), only polytomous items (generalized partial credit model), or a

Dear R-users, I'd like to announce the release of the new version of package `ltm' (i.e., ltm_0.8-0 soon available from CRAN) for Item Response Theory analyses. This package provides a flexible framework for analyzing dichotomous and polytomous data under IRT, including the Rasch model, the Two-Parameter Logistic model, Birnbaum's Three-Parameter model, the Latent Trait model

Dear R-users, I'd like to announce the release of the new version of package `ltm' (i.e., ltm_0.8-0 soon available from CRAN) for Item Response Theory analyses. This package provides a flexible framework for analyzing dichotomous and polytomous data under IRT, including the Rasch model, the Two-Parameter Logistic model, Birnbaum's Three-Parameter model, the Latent Trait model

Dear All, I am Ph.D student at Chulalongkorn University in Thailand, I want to use Package 'sampleSection' to estimate missing data which generate under IRT model(3-PL); n<-500 ## number of examinee I<-20 ## number of items num.imp<-5 ##number of imputations p.missing<-c(0.09, 0.01) #prob of missing theta<-sort(rnorm(n,0,1)) #ability a<-rnorm(I,0.5,0.1) #discrimination

Hi All, does anyone know how to import binary .bed files generated by Plink (http://pngu.mgh.harvard.edu/~purcell/plink/ ) into R? the Plink FAQ explains how to conver other types of files, not the .bed. Cheers, Federico -- Federico C. F. Calboli Department of Epidemiology and Public Health Imperial College, St. Mary's Campus Norfolk Place, London W2 1PG Tel +44 (0)20 75941602 Fax

Hi Everybody, I have just been introduced to R and have used the ltm package for calibrating items under IRT. I have been able to get the item parameters using the fit function under different models. I am using the 2PL model. I have got the parameters for some 300 items from 15 different tests using the function fit. Now I need to automatically generate tests such that they have atleast a

Hello, I've already tried asking at the cwrRsync forums with no luck yet, so I thought I would try my luck here. According to the rsync man pages, with the -e option you can use other remote shells, and I had thought plink was one of them, but I could be wrong. I can't seem to find any information anywhere about the proper syntax. What I've been trying, are all kinds of combination

I a using plink on a large SNP dataset with a .map and .ped file. I want to get some sort of file say a list of all the SNPs that plink is saying that I have. ANyideas on how to do this? -- Thanks, Jim. [[alternative HTML version deleted]]

snpMatrix package is quite nice (read.plink())

hello R, This is about simulation in psychomtrics in IRT in R. I want to simulate b parameters(item difficulty) with moments of fixed values of mean, st.d, skewness and kurtosis. Is there any specific IRT package in R with those functions to control those moments? I have seen other programs that can control mean and st.d but not skewness and kurtosis. Thank you, helen L [[alternative HTML

Dear All, does anybody know of a package (working under Linux) for multilevel IRT modelling? I'd love to do this without having to go on WINSTEPS or the like.. thanks for the attention! Federico Andreis ----- Dr. Federico Andreis Universit? degli Studi di Milano-Bicocca, PhD Student MEB Department, Karolinska Institutet, Stockholm, Visiting PhD Student -- View this message in context:

Hello forum, I have developed an IRT model for a set of items on a large reference sample. I now want to use the IRT parameters that were estimated in the reference sample to score new individuals, one at a time. What R package(s) would allow me to do this? Also, several covariates were associated with item thresholds in the reference sample, so I was wondering if any programs can take

Using the grm function (graded response IRT model) in the ltm package I receive the following error: Error: subscript out of bounds for several scales I'd like to examine. Here's a small example that if run a few times will likley produce the error at least once ch<-array(round(runif(50,1,5)),c(10,5)) grm(ch,start.val="random") ## or

Hello R, I am looking for non-parametric simulation in IRT. Is there any IRT package that does non-parametric simulation? helen L [[alternative HTML version deleted]]