Milk is sold in packages (containers) of many different sizes. What is the “Best Practice” choice of unit of measurement for expressing the Unit Price of milk, which will enable consumers to compare the relative value of various containers of milk?
The answer is liter, and a corresponding unit for Unit Price of dollars per liter (or cents per milliliter). Note that the actual size of any particular container of milk is *not relevant* to the selection of the “best practice” unit for expressing the Unit Price! The multiple options permitted in NIST SP 1181; price per fluid ounce, price per pint, price per quart, and price per gallon, are ill-advised because they inhibit easy comparisons of value by consumers if they are applied indiscriminately at competing retail stores. Eugene Mechtly
