Data definition keywords

$Facets = number  (number of facets in data)

The number of facets which interact to make up each data observation.

 e.g., when there are examinees, items and judges, then $Facets = 3

 

$Flabel = number,name [,codes]  (name of facet)

The number of a facet and its label in text format, e.g., $Flabel = 2, Subjects

You may optionally append control codes to be transferred to Facets,

 

e.g., to specify that this is an anchored facet, $Flabel = 1, Judges, A

 

$Length = 0  (standard DOS input data lines)

Each line in the input data file ends with standard DOS Carriage Return-Line Feed codes. This is the usual format for DOS and ASCII files. It is the default.

 

$Length = number  (fixed length data lines)

Each line is of the same fixed length, (number) bytes long. This is sometimes required for files imported from other computer systems in fixed-length record format. E.g., $Length = 100, for records 100 characters long.

Sometimes there are "invisible" codes, particularly at the end of each line. Adjust the record length up or down one or two to allow for them. For instance, there are two invisible codes, "Carriage Return" and "Line Feed" at the end of each line in a DOS text file.

 

To verify that your $Length= instruction is correct, use a short keyword file such as:

$Input=lengthDAT.txt   your data file

$Output=testOUT.txt   a dummy output file

$Length=20     your best data file

$Facets=2     a dummy number of facets

$Print=$s1w5     the first five characters of each data record display on your screen.

Check that the 5 characters displayed on your screen are the first five characters of each record. If not, the $Length= value needs adjustment.

 

$Label = facet number [, element number] [, element name]

[, "anchor value+","+"group"]

(number/name of element)

defines the current element in the facet referenced by (facet number).

(facet number) is the number of the facet to which the current element belongs.

(element number) is the number of thee current element in the facet

(element name) is the descriptive identifying text label for the current element.

 

E.g., facet 2 references Items. Element 7, "Multiplication", is the current element in facet 2:  $Label = 2, 7, Multiplication

Either the element number or its name or both can be specified. If no number is given, then Facform will assign one.

 

"anchor value" is the logit anchor value (if any)

"group" is the element"s group number (if any)

E.g., an element with an anchor value of 2.35 logits:

$Label = 4,,Zoo,2.35

 

An element with anchor value of 0.0 in group 6

 $Label = 5,13,,"0.0,6"

 

An element with no anchor value, belonging to Group given by variable sex.

sex =2 ;male

$Label = 1,,Fred,","+Q(sex)

 

$Rating = number [, replications] (datum value)

This causes the specified observation, rating or counter to be written in Facets format into the $Output file. Blank ratings are bypassed, and not written into the $Output file. E.g., for a rating of 2 on a scale, $Rating=2

 

When there are identical replications of the same datum value with the exact same facets and element numbers, their number can be specified. E.g., for 103 ratings of 4 with the same facets and element numbers, $Rating=4,102

Replications with a count of 0 are treated as missing data and ignored. E.g., $rating=2,0

This is useful for entering tabular or survey data.

 

Decimal observations:

Observations records as decimals, e.g., 2.5, 1.23, must be transformed into integer values.

 

Examples:

data are  0.00 0.25 0.50 0.75 1.00  etc.

$rating = $N($S1W4)*4

 

data are in the range 1.00 to 9.99

since Facets understands data in the range 0 to 255, a valid transformation is:

$rating = $I(($N($S1W4)-1) * 28)

This gives ratings in the range 0 to 252.


Help for Facform Rasch Measurement Software: www.winsteps.com. Author: John Michael Linacre

For more information, contact info@winsteps.com or use the Contact Form
 

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Rasch Publications
Rasch Measurement Transactions (free, online) Rasch Measurement research papers (free, online) Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch Applying the Rasch Model 3rd. Ed., Bond & Fox Best Test Design, Wright & Stone
Rating Scale Analysis, Wright & Masters Introduction to Rasch Measurement, E. Smith & R. Smith Introduction to Many-Facet Rasch Measurement, Thomas Eckes Invariant Measurement with Raters and Rating Scales: Rasch Models for Rater-Mediated Assessments, George Engelhard, Jr. & Stefanie Wind Statistical Analyses for Language Testers, Rita Green
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar Journal of Applied Measurement Rasch models for measurement, David Andrich Constructing Measures, Mark Wilson Rasch Analysis in the Human Sciences, Boone, Stave, Yale
in Spanish: Análisis de Rasch para todos, Agustín Tristán Mediciones, Posicionamientos y Diagnósticos Competitivos, Juan Ramón Oreja Rodríguez
Winsteps Tutorials Facets Tutorials Rasch Discussion Groups

 

Coming Rasch-related Events
Jan. 5 - Feb. 2, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
Jan. 10-16, 2018, Wed.-Tues. In-person workshop: Advanced Course in Rasch Measurement Theory and the application of RUMM2030, Perth, Australia (D. Andrich), Announcement
Jan. 17-19, 2018, Wed.-Fri. Rasch Conference: Seventh International Conference on Probabilistic Models for Measurement, Matilda Bay Club, Perth, Australia, Website
Jan. 22-24, 2018, Mon-Wed. In-person workshop: Rasch Measurement for Everybody en español (A. Tristan, Winsteps), San Luis Potosi, Mexico. www.ieia.com.mx
April 10-12, 2018, Tues.-Thurs. Rasch Conference: IOMW, New York, NY, www.iomw.org
April 13-17, 2018, Fri.-Tues. AERA, New York, NY, www.aera.net
May 22 - 24, 2018, Tues.-Thur. EALTA 2018 pre-conference workshop (Introduction to Rasch measurement using WINSTEPS and FACETS, Thomas Eckes & Frank Weiss-Motz), https://ealta2018.testdaf.de
May 25 - June 22, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
June 27 - 29, 2018, Wed.-Fri. Measurement at the Crossroads: History, philosophy and sociology of measurement, Paris, France., https://measurement2018.sciencesconf.org
June 29 - July 27, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com
July 25 - July 27, 2018, Wed.-Fri. Pacific-Rim Objective Measurement Symposium (PROMS), (Preconference workshops July 23-24, 2018) Fudan University, Shanghai, China "Applying Rasch Measurement in Language Assessment and across the Human Sciences" www.promsociety.org
Aug. 10 - Sept. 7, 2018, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com
Sept. 3 - 6, 2018, Mon.-Thurs. IMEKO World Congress, Belfast, Northern Ireland www.imeko2018.org
Oct. 12 - Nov. 9, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com

 
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