This variable, described as the Highest Level of Schooling, implies a hierarchy of educational attainment; however, in a number of instances, the levels are not entirely hierarchical. For example, the placement of "Trades certificate or diploma" as a higher level of schooling than "Secondary (high) school graduation certificate" is justified on the basis of the fact that this educational qualification is obtained primarily for employment/occupational purposes by persons who were, on the whole, beyond the secondary (high) school age level at the time. However, a sizeable proportion of this group did not obtain their secondary (high) school graduation certificate which would, strictly speaking, be "out of line" in the hierarchy. In any event, placing this whole category below secondary would not necessarily resolve the problem, since at least some part of this group does have secondary (high) school graduation. It is for this reason that the data for trades (and college) certificates are separately disaggregated in the variable Schooling: Trades and College Certificates or Diplomas.

Another example in which the hierarchical element of this variable would be slightly askew is in the cases of persons who have completed both university and college education. A person who attended university and college, but possessed no degrees, certificates or diplomas, would nonetheless be situated at a "higher" level than a person who has college education only, but with a certificate or diploma.

*   Prior to 2001, the college sector was referred to as the "non-university sector". The term was changed to "college" to reflect more accurately the majority of the institutes in this sector, which includes non-degree granting institutions such as community colleges, CEGEPs, private business colleges and technical institutes.

**   In 1976 and 1971, this variable was denoted as "Level of Schooling". In 1971, it was defined as the "highest grade or year of elementary, secondary school or university ever attended and whether or not additional training in the form of vocational or postsecondary non-university was present". In 1976, the definition was slightly revised to emphasize completion (rather than attendance) beyond the secondary level: "Level of schooling" referred to the highest grade or year of elementary/secondary school attended, or the highest year of postsecondary non-university or university completed by the person.

***   In 1961, the elementary, secondary and university levels were combined directly in one question, and the question referred to the "highest grade or year of schooling ever attended", not necessarily completed. The variable itself was called "Highest Grade Attended".