[1][2] It is considered the first viable and a still leading explanation for mid-twentieth century baby booms.
[3][4] The hypothesis as formulated by Richard Easterlin presumes that material aspirations are determined by experiences rooted in family background: he assumes first that young couples try to achieve a standard of living equal to or better than they had when they grew up.
If income is high relative to aspirations and jobs are plentiful, it will be easier to marry young and have more children and still match that standard of living.
But when jobs are scarce, couples who try to keep that standard of living will wait to get married and have fewer children.
For Easterlin, the size of the cohort is a critical determinant of how easy it is to get a good job.