恩格尔数据（Engel data）.doc

恩格尔数据（Engel data） The Engel curve represents the amount demanded of a consumer at each level of income. The Engel curve of the consumer can be derived from the consumer income curve. It was named after Engel, a statistician in Germany in the late nineteenth Century. In the normal goods, the Engel curve is shifted from left to right, which indicates that the consumption of X increases with the increase of income, while the inferior goods, on the contrary, decrease with the increase of income. Engel has been working on the relationship between household income and spending. In 1857, he proposed the famous Engels law, that is, as the income increases, the proportion of food in total expenditure is down. From the statistical results, the small families around the world, from the country basically follow this law, so we often will Engel coefficient in the proportion of the total expenditure in the food as an indicator to measure the level of economic development. It is generally assumed that the economy with a Engel coefficient of more than 50% is still in a subsistence economy, while less than 30% is a rich economy. Of course, this standard is not absolute, individual economy may appear in a certain period of economic development and Engel coefficients deviate from the situation. Engel also found that as income increased, clothing, housing in the proportion of total expenditure remained unchanged, while luxury, education, entertainment, savings and other proportion is rising. The Engel curve can be expressed in terms of income elasticity. By listing statistics, Engel points out that a familys spending on food and other items depends on its income and total consumer spending. As income increases, spending on food will fall; spending on homes and clothing will remain the same; spending on other goods will increase. The result of this analysis is called Engels law. Characteristic Engel curve of different commodities The necessity Engel curve is concave, indicating that the