Outcomes‐based education (OBE), namely the emphasis in education systems on learning outcomes and their assessment, has had one of the largest and most significant impacts on postsecondary education (PSE) in recent decades. Not only does OBE present clear statements to describe students’ skills and abilities, it also provides the vehicle by which postsecondary institutions can assess and improve the quality of their programs and demonstrate the value of these programs to both employers and the general public. Ontario PSE institutions, colleges in particular, have long embraced OBE. From the development of postsecondary program standards that specify the vocational learning outcomes of their credentials, to the inclusion of general education requirements, and the introduction of outcomes that require graduates to demonstrate skills in communication, numeracy, critical thinking and problem solving, information management, interpersonal skills, and personal skills — known collectively as the essential employability skills (EES) — Ontario colleges have provided leadership in the development of OBE. However, this leadership is not as uniformly evident when we consider the assessment of learning outcomes. Whereas numerous assessment approaches, as well as research to support their validity as measures of student performance, have evolved at the vocational level, in the case of the essential skills, and primarily of critical thinking (CT) — the focus of this study — there is to date no definitive assessment strategy. This situation is compounded by an ongoing lack of common understanding and consensus of what constitutes an essential skill such as CT, and the abilities that demonstrate its attainment.