Ideality = Cost Harm Benefit.
Ideality is more powerful than value (= function/cost) as ideality covers both the good and bad outputs and all inputs (not just money, but time, assembly, maintenance, disposal etc.). This makes ideality a powerful, real measure of the cots and usefulness, the real ‘goodness’ of each the system. The inclusion of all harmful outputs ensures it is the best measure for most things including sustainability. It is a simple equation of sum of all benefits divided by the sum of all costs + harms.
