There are two main approaches to understand poverty. One is 'nutritional' approach, and the other one is 'relative deprivation' approach. Nutritional approach measures poverty in terms of minimum income. This approach is adopted by most of the developing countries. Developed countries adopted the approach of relative deprivation to measure poverty, because deprivation to food is not the major problem there.
Relative deprivation approach is based on social inequality. It compares the situation of an individual or the group with the rest of society. It considers poverty as the deprivation of essential requirements such as clothing, food, housing, medical facilities and education. This approach is better than the nutritional approach because nutritional approach ignores essential non-food requirements for human living.
This approach also highlights one of the major causes of social deviance in individuals. Depriving of something that they think they are entitled to leads to social deviance, resentment and crimes. This approach highlights the importance of reducing income inequalities. Because even if the wealth of everyone is increased, number of people living in relative poverty will not change.
However relative deprivation always exists in society because social and income inequalities are inevitable in society. If a person who cannot afford luxury car feels deprived, measurement of poverty will vary. There is a difference between wanting and deserving. It depends on individuals base of comparison. Hence some internal standards and benchmarks, against which to assess deprivation are required.