Yi-Hsin Chen, University of South Florida, Tampa, FL Isaac Li, University of South Florida, Tampa, FL Jeffrey D. Kromrey, University of South Florida, Tampa, FL
Just an experiment with a Winsteps control option: What happens if you enter random numbers to SAFILE.
CATEGORY PROBABILITIES table gets strange shaped curves. Reliability gets wacky/low.
Conclusion: You will definitely notice something wrong happened.
Winsteps reference: http://www.winsteps.com/winman/safile.htm
Rasch model analysis has the following set of advantages
Being logit scores, Rasch scores have no theoretical upper and lower boundary values (useful for statistical analysis) Rasch scores facilitate pretest and posttest comparison based on different set of test items (You can avoid taking identical test at pre and post) Rasch model can handle missing […]
#01 CHECK RESPONSE VALUES (IF THEY ARE CODED INTO CORRECT NUMERALS)
Items used for Rasch model are usually ordinal variables based on expression such as “Strongly agree,” Agree,” “Disagree,” and “Strongly Disagree.” Code these so that higher agreement receives higher numbers:
Strongly agree 4
Strongly Disagree 1
If by […]
Mike wrote this for me:
log (Pnij / Pni(j-1) ) = Bn – Di – Fj where Fj is the Andrich Threshold between categories j-1 and j.
For a Rasch/Winsteps analysis that includes anchored items (difficulty parameters are fixed based on a set of values previously calibrated; as opposed to estimating them fresh from the data), one can check Table 14.1 of Winsteps output provides various diagnostics statistics.
In educational evaluation field, we often have access to vertically equated scales. Scales means scores, measures, points. Vertically equated scores in the context of education are the ones that are comparable across grades, which means that you can pick a score from 5th grader and a score from 8th grader and consider them to be […]
Using PROC LOGISTIC to Estimate the Rasch Model
Tianshu Pan, Pearson Yumin Chen, the University of Texas Health Science Center at San Antonio ABSTRACT
This paper describes how to use PROC LOGISTIC to estimate the Rasch model and make its estimates consistent with the results of the standard Rasch model software WINSTEPS.
Can this be right? If right, it helps reduce the computational demand off the procedure. Page 4:
"When thousands of persons take a test, the procedure takes a long time to estimate the parameters. It is well known that the Rasch model gives the same parameter estimates for each person who receives the same […]
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