Students experience significant over- or underestimates in new program development when it follows the Personal Software Process (PSP) PROBE process. This TSP Symposium 2014 presentation overviews how this potential problem can be reduced or solved by extending the PSP PROBE process.
A strategy is to find a logical evaluation combination of the productivity, correlation, and β1 and β0 used in the PROBE process. The estimated average size and time for a new program to be developed are obtained when method C is selected. The estimated proxy size is obtained for the new program through the PSP relative size table applied to the conceptual design. The estimated average size replaces the estimated proxy size when a student selects method C. If the estimated average size is not reasonably consistent with the past productivity data, the student should select method D for the size estimate. The similar discussion holds for the time estimate.
Another extension that is effective in the PSP PROBE process is to allow selecting method A or B when high correlations are recognized between the estimate and actual values, regardless of whether β0 or β1 satisfies the desired conditions respectively described in the PSP PROBE process, although the PROBE process suggests selecting method C for these cases.
After this extended PROBE process was presented, PSP students demonstrated reaching fewer over- or underestimates on the size and time of new programs.