03-4 The Price Elasticity of Demand and Its Determinants Demand tends to be more elastic the larger the number of close substitutes if the good is a luxury. the more narrowly defined the market. the longer the time period. Economics ECONOMICS MANAGEMENT SCHOOL,TONGJI UNIVERSITYEconomics ECONOMICS & MANAGEMENT SCHOOL, TONGJI UNIVERSITY 03-4 The Price Elasticity of Demand and Its Determinants • Demand tends to be more elastic : – the larger the number of close substitutes. – if the good is a luxury. – the more narrowly defined the market. – the longer the time period