MIT's organization structure has changed over time. On the academic side the schools (Architecture and Planning, Engineering, Humanities, Arts and Social Sciences, Sloan School of Management and Science have remained constant. Within the schools departments have changed their names, moved between schools and merged. On the administrative side structure has changed more regularly with units being created, merging, and changing names much more often. In doing trend analysis it is important to document these changes and understand the effect of structural changes on the data that is available for use and analysis.