The phrase "a test length" is correct and usable in written English.
It can be used when referring to the duration or extent of a test, such as in educational or experimental contexts.
Example: "The instructor specified a test length of two hours to ensure all students had enough time to complete the exam."
Alternatives: "a duration of the test" or "the length of the test".
It was expected that CAT, with a shorter test length, can achieve a similar degree of measurement precision as NAT.
We programmed a VBA-Excel CAT module to (a) gather simulation data, (b) verify that CAT only needs a shorter test length to achieve the same measurement precision as non-adaptive testing, (c) illustrate how a tablet PC works graphically, and (d) report how the Rasch-specific quality control helps detect aberrant responses to ensure measurement quality.
Each of the four subscales contains six test items for a total test length of 24 items.
As shown in Table 2, CAT did not yield person measure estimates that were statistically different from non-adaptive testing (p =.78); and CAT had a shorter test length than NAT (p <.01).
NAT took all the 23 items, whereas CAT took an average test length of 13.42 items.
For example, standard psychometric formulae such as the Spearman-Brown formula for expressing the reliability of a total score as a function of test length, or Cronbach's alpha lower-bound for reliability are based on elaborations of CTT (see Lord and Novick [1968]).
The reason is that, in order to get a reliability of.90, the test length must be increased by a factor of 6, but then the budget allows for only 16 subjects instead of the original 50.
The results indicated both fit statistics were clearly a function of sample size, and test length to a lesser extent.
This included an unpaired t-test (age) and a Mann-Whitney U test (length of stay in the subacute rehabilitation unit).
In the numeracy data set, for a two-class classification scheme, 96.9% of the subjects were correctly classified with a more modest reduction in test length of 35.7%; a three-class scheme correctly classified 93.8% with a 17.7% reduction in test length.
