A procedural model is presented for the construction and validation of an attitude scale in vocational education; and the results of an instrumentation study using that model are discussed. The three-stage model is composed of: (1) stratification of the construct; (2) item construction and selection; and (3) item cluster analysis. In phase one, the following steps are used: defining the universe of the construct; listing the major components; subdividing each component thoroughly; editing to eliminate duplications and ambiguities; and submitting stratification for expert review. For phase two, the following procedure is used: building an item bank; insuring accuracy of meaning; editing the items; submitting items for expert review; administering the trial instrument; doing statistical analysis of the results and of the correlation of each item with all component subscores and with the total score; and selecting items for the final test form. For phase three, the procedure is composed of: administering the instrument to a second subset of the target population; computing item-to-subscore and item-to-total score correlations; and performing additional item-to-subscore correlations. (MH)