helps if you read the official sites or even search the forums, its answered already. But, for the sake of asking, I'll answer.
"Beginning with the June 2007 PCAT"
" * The Verbal Ability, Biology, Quantitative Ability, and Chemistry subtests will be reduced in length from 58 to 48 test items (the Reading Comprehension subtest will remain at 48 items). Of the 48 items for each multiple-choice subtest, 40 will be core items that count toward examinees'; scores, and 8 will be experimental items being field-tested for possible use as core items on future test forms.
* The Quantitative Ability subtest will no longer include geometry items but will now include basic math items, and the number of probability and statistics items will be increased.
* A second Writing subtest will be added. The shortening of the multiple-choice subtests will allow the addition of the second Writing subtest, while only lengthening of the test by five minutes overall. Scores for only one of the two Writing subtests will be reported to examinees and recipient schools. The other Writing subtest will be experimental, and scores for this subtest will not be reported.
* The PCAT Writing topics will state a problem, and examinees will be scored on how effectively they write an essay that is of sufficient length to adequately explain a solution to the problem. Separate scores will be reported for the Writing subtest: Conventions of Language (the use of appropriate and conventional grammar, punctuation, usage, and style) and Problem Solving (the ability to develop a convincing essay in support of a specific solution).
* The Writing scores will be assigned on a scale of 0 to 5.0 by highly trained scorers. The Conventions of Language score will be assigned by a single reader (e.g., 3.0). The Problem Solving score represents an average of scores assigned by two readers (e.g., 3.5). Verification procedures are in place to assure that the assigned scores are consistent with pre-established criteria for each score point.
* Along with the Writing scores, mean scores will also be reported that represent an average of all Writing scores earned by examinees taking the test during the same national test administration. These mean scores allow an examinee's performance to be compared to the average performance of other examinees writing on the same topic at the same time."