how does income cause a shift in the demand curve
Demand curve When income increases, the demand curve for normal goods shifts outward as more will be demanded at all prices, while the demand curve for inferior goods shifts inward due to the increased attainability of superior substitutes. With respect to related goods, when the price of a good (e.g. a hamburger) rises, the demand curve for substitute goods (e.g. chicken) shifts out, while the demand curve for complementary goods (e.g. tomato sauce) shifts in (i.e. there is more demand for substitute goods as they become more attractive in terms of value for money, while demand for complementary goods contracts in response to the contraction of quantity demanded of the underlying good).[5]
Household income in the United States One key measure is the real median level, meaning half of households have income above that level and half below, adjusted for inflation. According to the Census, this measure was $59,039 in 2016, a record high. This was the largest two year percentage increase on record.[1]