You will learn the practical aspects of data setup, analysis, output interpretation, fit analysis, differential item functioning, dimensionality and reporting. Psychometric software is software that is used for psychometric analysis of data from tests, questionnaires, or inventories reflecting latent psychoeducational variables. Precision of score estimates for the item set was analyzed. Psychometric software is software that is used for psychometric analysis of data from tests. Aug 06, 2017 winsteps does mantelhaenszel for dichotomies and mantel for polytomies which are a widelyused for dif detection, as well as a raschbased method. There are several columns in the dif analysis output. Aug 22, 2017 winsteps tutorial 2 unidimensionality and local independence in rasch. In making these tools available online some people ask if im giving. In other words, the dif analysis identifies items that are abnormally easy or difficult.
Nov 18, 2010 differential item functioning analysis of sub. Rasch analysis of the western ontario osteoarthritis of the shoulder index the danish version sahar moeini,1 jeppe v rasmussen,1 tobias w klausen,2 stig brorson1 1department of orthopedic surgery, 2department of hematology, herlev hospital, herlev, denmark purpose. Rasch specifies how persons, probes, prompts, raters, test items, tasks, etc. Beginning with the 202014 program year, an annual analysis of differential item functioning dif of multiplechoice items was implemented as a component of bias prevention. The scale was developed in an effort to better describe the participation of people living in middleincome and. Users report that, after initial familiarization, it is straightforward to use in combination with other software. The differential item functioning analysis software penfield, 2005 and the easy dif software gonz alez et al. Winsteps constructs rasch measures from simple rectangular data sets, usually of persons and items. Unidimensionality was checked through principal component analysis pca, along with infitoutfit statistics and dtf dif.
In the dif box specify the column in the person label that identifies the dif. Data were fitted to the rasch partial credit model with the winsteps program. Parametric equivalence between confirmatory factor analysis under the multiple indicators, multiple causes mimic model and the rasch model has been. What is the information in the dif analysis output. Differential item functioning dif an be investigated using logodds estimators, mantelhaenszel 1959 for dichotomies or mantel 1963 for polytomies. Winsteps and facets are software for rasch analysis published by. The differential item functioning analysis software penfield, 2005 and the easydif software gonz alez et al. If they have, use mforms to split those common items into separate items. A persons participation is acknowledged as an important outcome of the rehabilitation process. The two types of fit statistics infit and outfit were also measured. The western ontario osteoarthritis of the shoulder woos index is a diseasespecific, patient. Ppt dif analysis powerpoint presentation free to download.
Occurrences and sources of differential item functioning. Featured image all images latest this just in flickr commons occupy wall street flickr cover art usgs maps. References of noncommercial software for irt analyses. The mh dif method was conducted using the differential item functioning analysis system difas computer program penfield, 2005. Rasch analysis of the western ontario osteoarthritis of.
Average item scores for subgroups having the same overall score on the test are compared to determine whether the item is measuring in essentially the same way for all. Comparing difference of the estimates of the item difficulty between subgroups was as a dif contrast. Interpreting winsteps and facets output, second edition written by richard m. Differential item functioning dif analysis was performed, and fit statistics in combination with principal components analysis of the residuals were used to test the unidimensionality assumption. Infit statistics consist of meansquare mnsq values, and outfit statistics are. Summary dif chisquare is the sum of the tstatistic values from table 30. There have been comments that the winsteps and facets dif estimates computed as interaction terms, after the measure maineffects have been estimated may. The participation scale pscale is an instrument that was designed to assess the participation of individuals with a health condition or disability. There are many other software packages that can be used to conduct rasch or 1pl irt analysis and generate item calibrations, e. Winsteps is a program designed for analysis with the rasch model. Last, we examined differential item functioning dif of included pmq items for individuals with cervical vs noncervical sci using the mantel test. Modifying measures based on differential item functioning.
Column 1 of the person labels contains gender m or f and columns 78 contain grade level k12. Next analysis dif for each item item level was conducted by different methods. Methods this work specifically addressed the rasch model which is the subject of growing interest in the field of health owing to. I am analyzing test items from a language test for dif across gender, nationality, first language and age. Dif analysis winsteps column 20 with width 1 dif label start in person label column 20 dif label start in person label with a width 1 12 dif analysis winsteps press entry number press ok dif analysis winsteps this should be at least 0. Comparison of the software programs the analysis of characteristics and the comparison of the ezdif, difas and easydif programs took into account a number of. The dif measure item difficulty on the latent variable for person group 1 on item 1 is. It also provides readers with an overview of dif detection methods, a summary of dif studies in language testing, and an example of a fivestage method to conduct a rasch measurement approach to detect dif in a diagnostic english listening test using winsteps software. Is it possible to get winsteps to do the usual dif analysis rather than the winsteps implementation. The participants responses were coded dichotomously. Comparison of three software programs for evaluating dif by. Help for winsteps rasch measurement and rasch analysis software. Winsteps and facets are software for rasch analysis published by winsteps. Dif location is usually column number within person label field.
Specify dif for person classifying indicators in person labels. The level of matching between the items difficulty and persons ability was analyzed. As is commonly done, the total score was used as the matching. A program conducts analyses pertaining to differential item functioning dif, differential test functioning dtf, and differential step functioning dsf based on contingency table approaches. The significance level shows that the difference between the performance of. I have tabseparated data and my dif indicator is in a separate field from the person label. It is a generalization of the mantelhaenszel for stratified 2 x 2. This course will teach you how rasch analysis constructs linear measures from scored observations, such as responses to multiplechoice questions, likert scales, and qualityoflife assessments.
Enter the column of the dif field in the person label. Dif the more papers are published about dif detection, the more squirrelly eccentric, cunningly unforthcoming or reticent it becomes. A comparison of uniform dif effect size estimators under the. Full text of a users guide to winsteps ministep raschmodel computer programs. Detection of uniform differential item functioning dif within the rasch model typically employs null hypothesis testing with a concomitant consideration of effect size e.
While some psychometric analyses can be performed with standard statistical software like spss, most analyses require specialized tools. Rasch models are a family of probabilistic logistic models that map item difficulty or location, person ability, or score along the same latent trait. While some psychometric analyses can be performed with standard statistical software like. Differential item functioning of the geriatric depression scale in an asian population. No significant evidence of multidimensionality was found at this stage for any country.
The significance level shows that the difference between the performance of the groups on the item is significant. Pmc free article broekman bfp, nyunt sz, niti m, jin az, ko sm, kumar r, fones csl, ng tp. Comparison of three software programs for evaluating dif. This will show the dif for all items include 8, 10, 14 but using the purified scoring. I finally got around to creating the expanded model in a digital format, so here it is. Winsteps is windowsbased software which assists with many applications of the rasch model, particularly in the areas of educational testing, attitude surveys and rating scale analysis. Differential item functioning between ethnic groups in the epidemiological assessment of depression. Rasch scaling is often classified under item response theory, irt, or logitlinear models.
References of noncommercial software for irt analyses nina. Winsteps rasch measurement computer program users guide. Dif analysis were investigated to generate groupspecific estimates of the item difficulty driven from irt method using winsteps software. In the dif analysis the group from spain was designated as the reference group and the moroccan participants as the focal group. Previously, i had mentioned dif difficulty, importance, frequency analysis as a tool that i used in the military to determine if job tasks required training. Measuring differential item and test functioning across.
Note that jmetrik uses the cochranmantelhaenszel for stratified 2 x k tables. Data analysis rasch differential item functioning dif analyses conducted using winsteps software. Software sites tucows software library shareware cdroms software capsules compilation cdrom images zx spectrum doom level cd. Georges respiratory questionnaire in patients with copd using rasch model analysis. Comparing difference of the estimates of the item difficulty between subgroups was as a. This paper develops sas code to estimate the rasch model using proc logistic in order to produce results consistent or comparable with the estimates from winsteps. Results of dif analysis by mh and raschwelch methods were also obtained in winsteps. The second and third columns are the mantelhaesnzel chisquare and associated pvalue. We have no missing data, and i would like to use winsteps, but variation described in section 19. Unidimensionality was checked through principal component analysis pca, along with infitoutfit statistics and dtfdif. Sep 11, 2017 there are several columns in the dif analysis output. Table 30 supports the investigation of item bias, differential item functioning dif, i.
Occurrences and sources of differential item functioning dif. This will tell you if some of the common items have behaved differently in different sets. Analyzing differential item functioning dif with rasch winsteps. Full text of a users guide to winsteps ministep rasch. The r program i wrote accomplishes the task like this. Rasch measurement converts dichotomous and rating scale observations into linear measures. Dif measure is the same doing a full analysis of the data, outputting. In addition to several different software packages available to detect dif, there are also several different methods to compute dif. Differential item functioning dif is a statistical characteristic of an item that shows the extent to which the item might be measuring different abilities for members of separate subgroups. Average item scores for subgroups having the same overall score on the test are compared to determine whether the item is measuring in essentially the. Dif occurs when individuals of the same ability level but with different characteristics e.
However, for the remaining variables, i have several groups. It links qualitative analysis to quantitative methods. The partial credit model pcm was applied to the data. Winsteps tutorial 2 unidimensionality and local independence in rasch.
Many analysts have checked winsteps mh results against other computations and they agree. Rasch analysis of the oxford knee score sciencedirect. Differential item functioning dif in composite health. Analysis of differential item functioning on some timss. The sample is divided into difference classification groups also called reference groups and focal groups which are shown in table 30 and specified with dif. Dif columns within person label for table 30 winsteps. Oct 20, 2015 the psychometric properties of the gal. Rasch analysis software such as winsteps linacre, 2010a calculate dif and offer a significance level.
Winsteps also includes thin and thick matching capability. A comparison of uniform dif effect size estimators under. Rasch analysis is a method for obtaining objective, fundamental, linear measures qualified by standard errors and qualitycontrol fit statistics from. Pa faculty perceptions of supportive environment by age. This inconsistency may cause test developers or psychometricians to set aside their results since winsteps is the standard rasch model software. Analyzing differential item functioning dif with raschwinsteps. Methods this work specifically addressed the rasch model which is the subject of growing interest in the field of. This training emphasizes measurement concepts and winsteps rating scale analysis in education. A differential item functioning analysis of the eq5d in. The item measures by person class are plotted in the dif plot in table 30. Differential item functioning analysis of highstakes test in terms. For gender, the analysis is straightforward since the groups are obviously femalesmales. The winsteps dif analysis is similar to the mantelhaenszel method linacre, 2003. The displacement values can be requested by using winsteps.
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