The current study investigates the phenomenon of measurement invariance by examining the construct stability of a summative mathematics achievement instrument over time gleaned from an existing data set. In doing so, not only is the general question of measurement invariance of the particular instrument addressed, but also in the context of growth studies. The onus of the study as well as the results are presented in light of the current political context of large scale K-12 assessment and the shifting of emphasis from status to growth. As the reader will discover, great pressure is placed on results not necessarily intended to serve as the metric required by policy. The results and implications are framed in both measurement and practical contexts. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]