As was done with ETFs, divide the CEFs into categories - growth, muni, fixed income, preferred, bond etc. Add NAV or discount/premium to NAV in (RV col?). Use percent leverage (or some facsimile) in the (RS col?). A quality number/ranking (esp for bomds) as a function of AAA, AAb, B etc rated holdings perhaps in the (EY col?). More to come ... we'll see. No revolution required but evolution would be very nice.