As should have been clear from our earlier discussion of product design, we can think of product design as taking a "step back" from a process and analyzing the bigger picture. Previously, we saw this as defining our product for what it does rather than for the specific material that it is, so that we might step out of the box and perhaps choose a better material for the job.
In the context of designing/choosing reaction networks, another characteristic of product engineering is to step back and ask ourselves what is the best possible scenario, given the process being considered. Instead of focusing on what the current reaction network for making our material is, we focus on what the material itself is, and consider multiple networks that might get us there. In this way, we might first maximize our "best case" before we actually do the process engineering necessary to attempt to get as close as we can to that ideal.
The atom economy of a process is the theoretical maximum percentage of our feedstock's mass that could become product if both our yield and our conversion were 100%. It is calculated as the ratio of the molecular weight of the desired product and the sum of the molecular weights of the reactants used.
Define and calculate the "atom economy" of a process proposal