In recent years, procedures have been established in Flanders for "Prior Learning Assessment" (PLA) outside the formal learning circuit, of which the portfolio is a regular component. In order to maximize the possibilities of acknowledgement of prior learning assessment, the Flemish government is looking for a set of common criteria and principles for the PLA portfolio. Using intensive research, 30 PLA portfolio projects were inventoried. An in-depth analysis revealed that although certain standardization may be sought, a universal PLA portfolio is neither possible nor desirable without sacrificing functionality. Although this article focuses mainly on the design and the results of the present study, it also references PLA practices in the U.S. (Contains 3 tables and 1 footnote.)