Interdiction: In this research, for evaluating various economic - social projects, we use welfare economics approach function, in order to calculate the weight of welfare and the marginal utility of income or consumption. If the purpose of government policy from economic and social projects is increasing social welfare through resource allocation between income deciles (through increased consumption or income) so what weight would be appropriate for each docile? It should be mentioned that because the real per capita consumption of each decile is different from the other ones, so equal increases of per capita consumptions, would have different effects on social welfare.

Method: To calculate the weights, demand function of food is estimated by using dynamic ordinary least squares (DOLS).

Findings: Therefore the welfare weights are important in calculation of evaluation of government projects.

Discussion: Results suggest that in order to increase social welfare through resource allocation, different weights should be considered for each docile and after calculating the weight, government should choose the plans which results in the most benefits from different aspects (distributive or with Pareto efficiency).