Items on test score scales located at and below the Proficient cut score define the content area knowledge and skills required to achieve proficiency. Alternately, examinees who perform at the Proficient level on a test can be expected to be able to demonstrate that they have mastered most of the knowledge and skills represented by the items at and below the Proficient cut score. It is important that these items define intended knowledge and skills, especially increasing levels of knowledge and skills, on tests that are intended to portray achievement growth across grade levels. Previous studies show that coherent definitions of growth occur often as a result of good fortune rather than by design. In this paper, we use grades 3, 4, and 5 mathematics tests from a state assessment program to examine how well (a) descriptors for Proficient performance define achievement growth across grades, and (b) the knowledge and skill demands of test items that define Proficient performance at each grade level may or may not define achievement growth coherently. Our purpose is to demonstrate (a) the results of one state assessment program's first attempt to train item writers to hit assigned proficiency level targets, and (b) how those efforts support and undermine coherent inferences about what it means to achieve Proficient performance from one grade to the next. Item writers' accuracy in hitting proficiency level targets and resulting inferences about achievement growth are mixed but promising.