Average propensity to consume (as well as the marginal propensity to consume) is a concept developed by John Maynard Keynes to analyze the consumption function, which is a formula where total consumption expenditures (C) of a household consist of autonomous consumption (Ca) and income (Y) (or disposable income (YD)) multiplied by marginal propensity to consume (c or MPC). According to Keynes, the individual´s real income determines saving and consumption decisions. Consumption function: It can be also explained as spending on every monetary unit of income.