In the second step, readers must distinguish between "given" and "requested" information in the question (Clark and Haviland, 1977; Mosenthal and Kirsch, 1991). Given information is presumed to be true, and it conditions the requested information. Requested information, on the other hand, is the specific information being sought.

In the third step, readers must search and read (or read and search) a text or document to identify the necessary information that corresponds with information provided in the question and, in the case of multiple-choice items, in the list of choices. In carrying out this search, several matches may be tried before one or more adequate matches are achieved. If a literal or synonymous match is made between requested or given information and corresponding text or document information, readers may proceed to the next step. If such a match is not deemed adequate, readers may choose to make a match based on a low- or high-level text-based inference or on prior knowledge; or readers may recycle to the first step.

This test-taking model of reading can be applied to multiple-choice as well as open-ended tasks. Based on this model, Kirsch and Mosenthal identified three variables as being among the best predictors of task difficulty for the prose and document scales. Two additional variables were constructed for the quantitative scales. These variables (type of requested information, type of match, plausibility of distractors, type of calculation, and operation specificity) were described in the previous section and are elaborated in Appendix A.

In order to understand how these variables interact with one another to affect the difficulty of items developed for the IALS, each literacy scale will be characterized in terms of several exemplary tasks. Next, these variables will be evaluated in terms of their contribution toward explaining the placement of literacy tasks along their respective scales.

Characterizing prose literacy tasks

There are 34 tasks ordered along the IALS 500-point prose literacy scale. These tasks range in difficulty value from 188 to 377. The easiest task (receiving a difficulty value of 188) directs the reader to look at a medicine label to determine the "maximum number of days you should take this medicine." In terms of our process variables, type of match (TOM) was scored a 1 because the reader was required to locate a single piece of information that was literally stated in the medicine label. The label contained only one reference to number of days and this information was located under the label dosage. Type of information (TOI) was scored a 2 because it asked for a number of days, and plausibility of distractor (POD) received a 1 because there is no other reference to days in the medicine label.