Assign students to include a letter of justification with the completed portfolio. After students choose material for their portfolios, assign them to write a cover letter that puts into words the criteria they used for their choices. The letter becomes a statement of claims with written support describing specific evidence and should become the focus of evaluating the portfolio. Such a letter rounds out the portfolio. Not only is the content there to measure, but also the student's justification about how he/she measured the pieces.