This paper presents research and provides a method to ensure that parallel assessments, that are generated from a large test-item database, maintain equitable difficulty and content coverage each time the assessment is presented. To maintain fairness and validity it is important that all instances of an assessment, that is intended to test the same subject content, are presented to each test-taker without bias. The method described demonstrates how each test-item in an item bank (i) is assigned a difficulty rating using a recognized test-centered legally defensible cut-score determination method, (ii) assigned to either hard, moderate, or easy categories, and (iii) then selected in a stratified random selection fashion, by content and difficulty, to ensure equal content coverage and difficulty level within an acceptable range of the calculated cut score.