MODELS= assigns model types to items = R, dichotomy, rating or partial credit scale

Do not specify MODELS= unless you intend to use the "S" , "F" or "C" models.

MODELS =

Winsteps chooses the model-family based on MODELS=. Models=R (or MODELS= is omitted) is the rating-scale family of models which includes the Andrich Rating-Scale Model, the Masters Partial-Credit Model, the Grouped Rating-Scale Model and the Rasch Dichotomous Model.

MODELS= *file name

file containing details

MODELS = *

in-line list. See Example 2.

MODELS = codes

codes for item groups, R (standard). S (success), F (failure), D (dichotomy), C (consecutive dichotomy).  Items are assigned to the model for which the serial location in the MODELS= string matches the item sequence number. When only one letter is specified with MODELS=, e.g., MODELS=R, all items are analyzed using that model.

MODELS = D

Rasch dichotomous model. Dichotomous data. Items with only two response categories are analyzed using the Rasch dichotomous model, regardless of what model is specified unless they are grouped with a polytomous item.

MODELS = R

ISGROUPS= omitted, Andrich "Rating Scale" model

ISGROUPS=0, Masters' "Partial Credit" model

ISGROUPS=11222 or something else, the Grouped Rating Scale Model

Andrich D. (1978) A rating scale formulation for ordered response categories. Psychometrika, 43, 561-573.

Masters G.N. (1982) A Rasch model for partial credit scoring. Psychometrika, 47, 149-174.

Linacre J.M. (2000) Comparing and Choosing between "Partial Credit Models" (PCM) and "Rating Scale Models" (RSM). www.rasch.org/rmt/rmt143k.htm

MODELS = S

uses the Rasch dichotomous model and the Glas-Verhelst "Success" (growth) model, also called the "Steps" Model (Verhelst, Glas, de Vries, 1997). If and only if the person succeeds on the first category, another category is offered until the person fails, or the categories are exhausted, e.g. an arithmetic item, on which a person is first rated on success on addition, then, if successful, on multiplication, then, if successful, on division etc. "Scaffolded" items can function this way. This is a continuation ratio model parameterized as a Rasch model with missing data on unreached categories. Verhelst N.D., Glas C.A.W. & De Vries H.H. (1997) A Steps model to analyze partial credit. In W.J. van der Linden & R.K. Hambleton (Eds.), Handbook of modern item response theory (pp. 123 - 138) New York: Springer

MODELS = F

uses the Rasch dichotomous model and the Linacre "Failure" (mastery) model. If a person succeeds on the first category, top rating is given and no further categories are offered. On failure, the next lower category is administered until success is achieved, or categories are exhausted. This is a continuation ratio model parameterized as a Rasch model with missing data on unreached categories. The Success and Failure model computations were revised at Winsteps version 3.36, August 2002.

Recommendation: Instead of an F-type polytomy, model each step to be a dichotomy: 1=succeeded, 0=failed, missing=not reached. This facilitates much more powerful diagnosis of the functioning of the failure process.

Linacre J.M. (1991) Beyond Partial Credit: Rasch Success and Failure Models. www.rasch.org/rmt/rmt52j.htm

MODELS = C

the rating scale is analyzed as consecutive dichotomies with one dichotomy for each category boundary. Bradley C., Massof R. (2018) Method of successive dichotomizations: An improved method for estimating measures of latent variables from rating scale data. PLoS One.

 

Please look at the output in Table 3.2, 3.3, .... to see exactly how the data have been modeled.

 

Use one character per item with no blanks

  NI=8

  MODELS='RSRFRSRR' ; this also forces ISGROUPS=0 to be the default

 

When XWIDE=2, you can also use one character per XWIDE with blanks,

  NI=8

  XWIDE=2

  MODELS=' R S R F R S R R' ; this also forces ISGROUPS=0 to be the default

 

Example 1: All items are to be modeled with the "Success" model.

  MODELS=S ; the Success model

 

Example 2: A competency test consists of 3 success items followed by 2 failure items and then 10 dichotomies. The dichotomies are to be reported as one grouping.

  NI=15  fifteen items

  MODELS=SSSFFRRRRRRRRRR ; matching models: ; forces ISGROUPS=0 to be the default

  ISGROUPS=000001111111111 ; dichotomies grouped: overriding the default ISGROUPS=0 

or

  MODELS=*

  1-3 S

  4 F

  5 F

  6-15 R

  *

 


 

MODELS= Demonstration

 

Score on item

RSM Andrich thresholds

RSM Thurstone thresholds

Consecutive Dichotomy  thresholds

Success Model thresholds

Failure Model thresholds

5

.00

.68

1.61

 .00

1.61

4

.00

.24

.69

 -.69

1.38

3

.00

.00

 .00

-1.10

1.10

2

.00

-.24

-.69

-1.38

.69

1

.00

-.68

-1.61

-1.61

.00

0

-

 

-

-

-

 

This control and data file demonstrates that the C, S and F models produce the same Andrich thresholds as the equivalent sets of dichotomous items. The standard errors and fit statistics differ because the sets of dichotomous items are treated as independent, but the rating scale categories are dependent.

 

TITLE = MODELS= Demonstration

ITEM1 = 1

NI=19

NAME1 = 21 ; the score on the item or item set

NAMELEN = 1

CODES=012345

ISGROUPS=0 ; each item has its own rating or other scale

; MODELS=

; R = RATING SCALE MODEL AND SIMPLE DICHOTOMIES

; C = CONSECUTIVE DICHOTOMIZATION

; S = SUCCESS MODEL

; F = FAILURE MODEL

MODELS=RCRRRRRSRRRRRFRRRRR

OFILE=RCSF.txt

PAFILE=*

1-6 0  ; anchor at zero to avoid item interactions

*

TFILE=*

14.1  ; item difficulties

3.2+  ; rating scales

*

CMATRIX = No ; omit confusiion matrix

&END

1.  RATING-SCALE MODEL

2.  CONSECUTIVE DICHOTOMIZATION

3.  5 CONSECUTIVE DICHOTOMY

4.  4 CONSECUTIVE DICHOTOMY

5.  3 CONSECUTIVE DICHOTOMY

6.  2 CONSECUTIVE DICHOTOMY

7.  1 CONSECUTIVE DICHOTOMY

8.  SUCCESS MODEL

9.  5 SUCCESS DICHOTOMY

10. 4 SUCCESS DICHOTOMY

11. 3 SUCCESS DICHOTOMY

12. 2 SUCCESS DICHOTOMY

13. 1 SUCCESS DICHOTOMY

14. FAILURE MODEL

15. 5 FAILURE DICHOTOMY

16. 4 FAILURE DICHOTOMY

17. 3 FAILURE DICHOTOMY

18. 2 FAILURE DICHOTOMY

19. 1 FAILURE DICHOTOMY

END LABELS

551111151111151.... 5

4411110411110401... 4

331110031110.3001.. 3

22110002110..20001. 2

1110000110...100001 1

000000000....000000 0


Help for Winsteps Rasch Measurement and Rasch Analysis Software: www.winsteps.com. Author: John Michael Linacre

Facets Rasch measurement software. Buy for $149. & site licenses. Freeware student/evaluation Minifac download
Winsteps Rasch measurement software. Buy for $149. & site licenses. Freeware student/evaluation Ministep download

Rasch Books and Publications: Winsteps and Facets
Applying the Rasch Model (Winsteps, Facets) 4th Ed., Bond, Yan, Heene Advances in Rasch Analyses in the Human Sciences (Winsteps, Facets) 1st Ed., Boone, Staver Advances in Applications of Rasch Measurement in Science Education, X. Liu & W. J. Boone Rasch Analysis in the Human Sciences (Winsteps) Boone, Staver, Yale Appliquer le modèle de Rasch: Défis et pistes de solution (Winsteps) E. Dionne, S. Béland
Introduction to Many-Facet Rasch Measurement (Facets), Thomas Eckes Rasch Models for Solving Measurement Problems (Facets), George Engelhard, Jr. & Jue Wang Statistical Analyses for Language Testers (Facets), Rita Green Invariant Measurement with Raters and Rating Scales: Rasch Models for Rater-Mediated Assessments (Facets), George Engelhard, Jr. & Stefanie Wind Aplicação do Modelo de Rasch (Português), de Bond, Trevor G., Fox, Christine M
Exploring Rating Scale Functioning for Survey Research (R, Facets), Stefanie Wind Rasch Measurement: Applications, Khine Winsteps Tutorials - free
Facets Tutorials - free
Many-Facet Rasch Measurement (Facets) - free, J.M. Linacre Fairness, Justice and Language Assessment (Winsteps, Facets), McNamara, Knoch, Fan
Other Rasch-Related Resources: Rasch Measurement YouTube Channel
Rasch Measurement Transactions & Rasch Measurement research papers - free An Introduction to the Rasch Model with Examples in R (eRm, etc.), Debelak, Strobl, Zeigenfuse Rasch Measurement Theory Analysis in R, Wind, Hua Applying the Rasch Model in Social Sciences Using R, Lamprianou Journal of Applied Measurement
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch Rasch Models for Measurement, David Andrich Constructing Measures, Mark Wilson Best Test Design - free, Wright & Stone
Rating Scale Analysis - free, Wright & Masters
Virtual Standard Setting: Setting Cut Scores, Charalambos Kollias Diseño de Mejores Pruebas - free, Spanish Best Test Design A Course in Rasch Measurement Theory, Andrich, Marais Rasch Models in Health, Christensen, Kreiner, Mesba Multivariate and Mixture Distribution Rasch Models, von Davier, Carstensen
As an Amazon Associate I earn from qualifying purchases. This does not change what you pay.

facebook Forum: Rasch Measurement Forum to discuss any Rasch-related topic

To receive News Emails about Winsteps and Facets by subscribing to the Winsteps.com email list,
enter your email address here:

I want to Subscribe: & click below
I want to Unsubscribe: & click below

Please set your SPAM filter to accept emails from Winsteps.com
The Winsteps.com email list is only used to email information about Winsteps, Facets and associated Rasch Measurement activities. Your email address is not shared with third-parties. Every email sent from the list includes the option to unsubscribe.

Questions, Suggestions? Want to update Winsteps or Facets? Please email Mike Linacre, author of Winsteps mike@winsteps.com


State-of-the-art : single-user and site licenses : free student/evaluation versions : download immediately : instructional PDFs : user forum : assistance by email : bugs fixed fast : free update eligibility : backwards compatible : money back if not satisfied
 
Rasch, Winsteps, Facets online Tutorials


 

 
Coming Rasch-related Events
May 17 - June 21, 2024, Fri.-Fri. On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
June 12 - 14, 2024, Wed.-Fri. 1st Scandinavian Applied Measurement Conference, Kristianstad University, Kristianstad, Sweden http://www.hkr.se/samc2024
June 21 - July 19, 2024, Fri.-Fri. On-line workshop: Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com
Aug. 5 - Aug. 6, 2024, Fri.-Fri. 2024 Inaugural Conference of the Society for the Study of Measurement (Berkeley, CA), Call for Proposals
Aug. 9 - Sept. 6, 2024, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com
Oct. 4 - Nov. 8, 2024, Fri.-Fri. On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
Jan. 17 - Feb. 21, 2025, Fri.-Fri. On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
May 16 - June 20, 2025, Fri.-Fri. On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
June 20 - July 18, 2025, Fri.-Fri. On-line workshop: Rasch Measurement - Further Topics (E. Smith, Facets), www.statistics.com
Oct. 3 - Nov. 7, 2025, Fri.-Fri. On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com

 

 

Our current URL is www.winsteps.com

Winsteps® is a registered trademark