Necessary good

As necessary good (or Sättigungsgut ) is referred to in the national economy and there, especially in the Mikroökonomie a class of goods where the demand increase continuously (the Engel curve decreases runs correspondingly concave) until the saturation level is reached (income elasticity: 0 <E <1).

Definitions

This article is based on the following, probably the most common, definition of a necessary good.

A good is said to be necessary when the increase in demand decreases with increasing income.

properties

When adding the definition of income elasticity , a good is necessary if the income elasticity is less than 1 and greater than 0.

It should also be noted that when classifying a good as necessary, the external circumstances (prices, absolute income, preferences) are decisive.

Examples

Above all, food and luxury goods, since even with rising incomes can only be consumed until the increase in demand falls and the saturation level is reached, are examples of necessary goods.

Individual evidence

1. ↑ Michael Heine and Hansjörg Herr: Economics. Paradigm-oriented introduction to micro- and macroeconomics. Oldenbourg, Munich 2013, ISBN 978-3-486-71523-1 .
2. ↑ Jonas Regul: Value of inferior goods . In: Cengage Learning . Cengage, April 2018.
3. ↑ ^{a b} Rudolf Peto: Macroeconomics and economic policy application . 2014, ISBN 3-486-84290-0 .
4. ↑ Unfortunately, this is also inconsistent. It is usually defined by, cf. the article income elasticity . ${\displaystyle \eta _{i}\equiv {\frac {\partial x_{i}(\mathbf {p} ,y)}{\partial y}}{\frac {y}{x_{i}(\mathbf {p} ,y)}}}$