Inferior goods

…The sensitivities of demand xi _with respect to pi _, pj _, and Y are expressed by ₍ pi / xi )( _∂xi / _∂pi ), ( pj / _xi ) ( _∂xi / ∂pj ), and ( Y / xi _{) (} ∂xi / ∂pj ) , which are called _{the price} elasticity , cross elasticity, and income elasticity _of demand, respectively ₍ see Elasticity). Furthermore, goods with positive income elasticity are defined as normal goods, and goods with negative income elasticity are defined as inferior goods. Two goods with positive cross elasticity are called substitutes for each other (strictly speaking, gross substitutes), and two goods with negative cross elasticity are called complements of each other (strictly speaking, gross complements). Other known effects include the bandwagon effect, in which the overall consumption of a good has a positive effect on individual demand, the snob effect, which has a negative effect, and the Veblen effect, in which the higher the price of a good, the stronger the ostentatious effect, which has a positive effect on demand.

*Some of the terminology that refers to "inferior goods" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…また，需要x_iのp_i,p_jおよびYに関する感応度は(p_i/x_i)(∂x_i/∂p_i)，(p_j/x_i)(∂x_i/∂p_j)および(Y/x_i)(∂x_i/∂p_j)によって表され，それぞれ需要の価格弾力性，交差弾力性，および所得弾力性と呼ばれている(〈弾力性〉の項参照)。さらに，所得弾力性が正値をとる財は正常財，負値をとる財は下級財と定義され，交差弾力性が正となる2財は互いに代替財(厳密には粗代替財)，負となる2財は互いに補完財(厳密には粗補完財)と呼ばれる。　なお，このほかに，財の全体的消費量が個別需要に正の効果を及ぼすバンドワゴン効果，負の効果を及ぼすスノッブ効果，さらに財価格が高いほど見せびらかす効果が強まり需要に正の影響を与えるというベブレン効果などが知られている。…

※「下級財」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報