The positions of reading passages and items varied across students, while the positions of the items within each passage remained unchanged.
Unlike the paper pencil version, the computer-based version was administered to the students by randomizing the positions of the items across the students.
In the current study, instead of a categorical grouping variable, item position will be used as a continuous, explanatory variable to predict whether there is any relationship between item difficulty and the varying positions of the items on the test.
This finding suggests that as the positions of the items increase (e.g., the item moves from the 1st position to the 15th position), the difficulties of the items also increase and thus the probability of correctly answering the items decrease.
For example, in a reading assessment where items are often connected to a reading passage, it is challenging to maintain the original positions of the items from field test to final form to eliminate the possibility of any position effects (Meyers et al. 2009).
In that case, the relative position of the items, i.e. the ratio between the location values of any two items, must be constant along the trait.
The map of persons and items is useful for comparing the range and position of the items and can be also utilized to measure person's distributions.
To give a better graphical display, the length of the ranking vectors can be scaled to fit the position of the items.
For instance, leave a coffee mug you used at your boyfriend's place out on the coffee table when you leave, or change the position of the items on his nightstand.
