What is the difference between atom economy and percentage yield?

First I will start by defining the two terms. Atom economy is calculated by dividing the total relative molecular mass of the desired product over the total relative molecular mass of the reactants. You can use the total relative mass of reactants or products here because it should be the same value. No atoms are made or lost in a reaction. Percentage yield on the other hand is calculated by dividing the mass of the total product made by the maximum theoretical mass of product. Difference between the two is that atom economy looks at the amount of the material that we start with that actually is useful. It is used to assess how sustainable a reaction is. It also indicates for economically feasible a reaction is, as a lot of the reactants may jsut become waste products. Percentage yield tells us how successful a reaction is. A reaction may not be able to give the maximum theoretical yield for a range of reasons, such as a reversible reaction not going to completion or losing some of the product in filtering. Reactions can have a high atom economy and a low yield or a high percentage yield and low atom economy.