CRA suffers from additional methodological problems. If there were no public programs to protect drinking water in this country, drinking water would rank among the highest risks, as it does in many developing countries. However, because there are protection programs, the current risks from drinking water in the U.S. are not great. We cannot do zero-based budgeting if the analysis of risks assumes current levels of spending. Most importantly, CRA deals only with risk, and risk is only one of several factors that should enter into most government decisions.
Cost is an obvious other factor.
To the extent that decisions should be based on cost-benefit analysis, risk gives only the benefit side of the equation. Furthermore, you cannot do a cost-benefit analysis of a problem, only of a solution. Whereas CRA deals with problems, cost-benefit deals with solutions. So getting from one type of analysis to the other is not simple because the two types of analysis are analyzing two different sets of things. Aside from risks and costs, public decision makers need to consider such things as due process, administrative feasibility, legality, and political support.