﻿ Facets, elements and observations

Facets, elements and observations

Facets data are constructed from facets, elements and observations:


A. The facets. Each facet is a set of persons or items or judges or tasks or times of day or other aspects of the situation which generated the data. There can be up to 255 facets.


B. The identifiers or elements in each facets. Each element in a facet is identified by an ordinal number in the range 1 - 2,147,483,648. Elements numbers can be omitted or skipped, and the same numbers can be used in different facets, e.g. the judges can be numbered 1,2,5,8 and the examinees 2,7,8,12.


Element number 0 is used when a facet did not participate in an observation, e.g., when multiple-choice question (MCQ) items are combined with essay ratings, judge 0 specifies that the MCQ observation did not require a judge.


C. The observation, rating, or count. This is a digit in the range 0-255. A missing or negative value implies that this rating is not to be included in the analysis. Since Facets ignores blank ratings, Facform also ignores them, unless instructed to converted them to a non-blank value.


Facets data are recorded by position. For each observations, the element numbers of the facets are entered in order by facet, followed by the data value. An example of a data record is:



which means that the combination of

"2" (element 2 of facet 1) and

"3" (element 3 of facet 3),

 resulted in a rating or count of "1".

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

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