It depends on the items and the time period. Although early versions of UCUES date back to 1996, the survey has undergone periodic changes since then. For example, in 2006 and 2014 substantial changes were made to the survey (e.g., the addition of some questions and the removal of others). Other changes that have occured over the years include survey items being relocated from one section of the survey to a different section, a consolidation and reduction of the modules contained within the survey, and changes in the question wording or response options. Thus, comparisons across years should take these factors into account (i.e., when possible, only compare identically worded and located items across UCUES administrations).