In 1963 economist Mollie Orshansky created this "line" by multiplying the cost of an adequate diet by 3
[DOC] [TLE] Mollie Orshansky's Strategy to Poverty Measurement as a ... - jstor [PAR] Review ofAgricultural Economics-Volume 30, Number 3-Pages 572-580 ... 
Orshansky (1963), and further refined in Orshansky (1965).