I have done a multiple regression analysis of a group of design variables for a system I am analyzing. From this I determined the standardized regression coefficients. All of the variables fall into one of two groups, architectural variables and control variables. I would like to determine the relative importance of each group of variables, so that I can make a claim to the effect of "the architectural variables are twice as important as the control variables for this system". Is it acceptable if I simply sum the standardized regression coefficients from all the variables in each group and compare these two numbers?