The "Stanford-B" effect assumes that prior learning can be captured and utilized on new designs given that the new design is consistent with old design and its complexity is similar. "Stanford-B" factors generally range from 1 to 10 with four being the most common used. Agreement needs to be reached between the buyer and seller on the "B" factor. After the "B" factor has been agreed to it is possible to estimate the cumulative average labor hours needed to produce the a quantity of parts of the new design.