The study investigated the effect of "item density" on item difficulty in passage-related language tests. Item density refers to the number and frequency of items in relation to clear text. The format used was a passage with underlinings to signal the language situations out of which the items were constructed. American College Testing Program (ACT) Assessment experimental units were constructed that varied the number of items per sentence of text within the passage. Each of the 3 versions of the text contained 30 items and the proportional representation across the 5 item classifications was the same. Results suggest that item density significantly influences item difficulty. However, it could not be discerned which language classifications were particularly susceptible to the impact. The study suggested that the quality of passage-related language formats would be enhanced if test constructors presented no more than two test items per sentence. Achieving appropriate item density in these formats would seem to improve validity and reliability. (DWH)