Work-based learning (WBL) differs from work experiences gained in regular youth jobs because WBL is intentionally structured to promote learning by linking work with school. Five main purposes of WBL have been identified: enhancing students' motivation and academic achievement; increasing personal and social competence related to work in general; fostering a broad understanding of an occupation or industry; providing career exploration and planning; and imparting knowledge or skills related to employment in particular occupations or more generic work competencies. The key structural dimensions for delivering WBL are as follows: location (on campus or off); supervision (teachers or employers); time (during or after school hours); compensation (pay or school credit); and participation (individually or in groups). A recent study of students' WBL experiences outlined three aspects of the workplace learning environment that should be considered when assessing the quality of teaching and learning at work: types of tasks students perform and the social context in which those tasks are established, accomplished, and processed; influence of the community of practice (how it teaches students what they need to know and how it defines the student's role); and worksite pedagogy (the training philosophy and practices for promoting learning at work). (Contains 33 references) (MN)