Portfolio assessment refers to the assessment of a collection of a student's work, in most cases his or her best work. A portfolio most often includes a series of products that have been designed to specifically assess certain abilities. Both the goals and the evidence that will be considered acceptable and appropriate for meeting them are developed and expressed clearly and explicitly early in the process. A portfolio documents the range of a student's activities and accomplishment, and it illustrates the student's performance and improvement over time (Collin, 1992; McMillan, 2001; Smith, Smith, & DeLisi, 2001).