abstract
The design evolution of two important process-based technologies, PCR DNA amplification and ERP software, was punctuated by discrete leaps in scale. From comparison of these technologies we distill a stage model centering on the phenomenon of increasing scale while clarifying just what the concept of scale means in the context of process-based technologies. Process-based technologies turn out to be distinctive because of the temporal aspect of scaling; although scaling up usually refers to spatial dimensions of scale, this research highlights the temporal dimension to scale. Temporal scaling can be complemented by multiplicative scaling, a design innovation enabling multiple processes to be performed in parallel. After highlighting different patterns of innovation from those that characterize manufactured products as conveyed by classic product-process lifecycle models, we reconcile our stage model with these classic lifecycle models: although the sequence of innovation phases is different, the overall evolution of the underlying economic logic motivating technology developers is actually rather similar.