OCR 9-1 GCSE Design & Technology Portfolio Mapping Evidence The spreadsheet calculates the average for each strand (1-5), when marks are entered for each statement, then an overall total is calculated. Students and teachers can also map evidence of the slides which refer to each statement. This has proven to be very useful, as students have taken responsibility for each strand and are able to calculate their own potential marks. It has also been useful to transfer data from the spreadsheet to the CRF forms.