Educational reformists have asserted that collaborative relationships between universities and local education agencies must be firmly established if improvements are to occur in the preservice preparation of school administrators. One collaboration format involves practica and other field-based learning opportunities for aspiring administrators. Although the emerging "learning by doing" emphasis might seem appropriate, uncritical and wholesale acceptance of this approach would be a big mistake. This paper identifies some common assumptions about practica and raises additional issues that need to be considered by policy-makers and designers of administrator preparation programs. First the rationale for practica is examined, using the literature on preservice teacher education, because scant material pertaining to administrator field-based practices is available. Next, the supposed benefits, such as assessing career commitment, refining school goals, practicing in realistic settings, developing competence, and promoting personal professional development, are examined and critiqued for programmatic shortcomings. The same treatment is accorded assumptions related to structure, including implementation and ultimate effectiveness considerations. To counteract the paper's pessimistic observations, several recommendations concerning program control, needed skills, administrator role models, and research needs are provided. Included are seven references. (MLH)