A follow-up study to Stanford University's Teacher Assessment Project (TAP) investigated captioning as a means of making sense of portfolios and explored how the captioning process might provide a way to use student portfolios to link student assessment and teacher assessment. Each of four teachers (three third grade and one fourth grade) from the TAP's literacy component sample, whose portfolios and assessment center performances were rated as impressive, submitted five student portfolios and were interviewed. Each portfolio included a teacher-written caption consisting of five elements: identification of the document; description of the instructional context; explanation of purpose; interpretation of student performance; and application of assessment information to instruction. Results indicated that: (1) all teachers appeared to rely on particular kinds of work samples to assess student progress in both reading and writing; (2) the majority of captions contained descriptive elements but omitted one or more interpretative elements; (3) all teachers felt the task of captioning portfolio documents was novel and time-consuming; and (4) the reflective interpretation that was lacking in two teachers' captions became evident during the interviews. Findings suggest that captions were essential to understand how work samples purporting to show student learning reflected the teacher's instructional intentions. (A thoroughly captioned portfolio document is included.) (RS)