In specific cases, there are small deviations between these methods that can be attributed to the steady state assumption implicit in the derivation of the copolymer equation. As mentioned above, this assumption implies that the entire distribution of monomer run lengths already exists at time zero. In other words, depropagation reactions can occur immediately. For polymers that ultimately reach an appreciable length (degrees of polymerization >~100), such an assumption causes only A critical point worth justification and further discussion is the lumping of multiple rate coefficients into reactivity ratios to reduce the number of fit parameters required (e.g., 𝑟 ! = 𝑘 ' /𝑘 8