In 1931, Lionel Robbins famously wrote "Economics is the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses". This drew a line of demarcation between mainstream economics and other disciplines and schools studying the economy.
Lionel Robbins in 1931 defined economics as "the science that investigates how individuals manage their actions given scarce resources with various uses." This definition helped to distinguish the main stream of economics from related academic areas studying economies.