A key purpose and consequence of Rasch analysis is the construction of variables. A variable can be presented in tabular form or as a map of a line along which all the elements (usually persons and items) are located by their measures. Often we identify these elements merely by sequence numbers, but much more meaning is conveyed when the element labels contain important qualitative information.
A few simple steps in naming elements in a program control file can improve the speed and ease with which information is extracted from program output. The same principles apply to naming items and persons. Here is a sample item "name" and an explanation of the naming system.
Original Test Item:
276. Which plant is one stick tall?
[Printed here is an illustration of one stick and several plants]
Suggested name: Q276/Z3-WhchPlant1StickTallP?
Explanation:
Q276 The question number of the item.
/ A symbol separating information in the name.
Z3 This question was part of a test of 30 mastery question sets (3 items per set). The "Z" identifies the item as part of the 26th administered mastery question set. The "3" following the "Z" indicates that this item is the third question presented in the 26th set.
- A symbol separating information in the name.
"WhchPlant1StickTall" To make the best use of the space available for naming, start each new word with an uppercase letter. Don't leave blanks. The composite word is an abbreviation of the item's text.
P The item included a "P"icture.
? The item was written as a question.
Other codes come to mind: G for graph, T/F for true/false, ?B for questions which involve selecting the best answer. Similarly, person labels are much more informative when they include abbreviations for gender, age, educational level, experience, ethnicity and the like. Developing compact, informative, yet understandable, naming schemes allows you and your readers, novice or expert, to obtain greater understanding of your variables.
Naming Elements for Understanding, W Boone … Rasch Measurement Transactions, 1991, 5:1 p. 130
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