According to Professor Mehta, the group of individuals is a society. Therefore, social welfare is certainly related to individual welfare. As social welfare is a mental and psychological concept, its objective measurement cannot be made, but we can compare social welfare in one situation to a different situation.

• Profit : According to professor Mehta, profit is the reward received in return for the risk of the entrepreneur. It is only achieved in dynamic position. The profit is received in return of carrying the risk or in the form of unusual or unexpected receivables. The gain achieved in the dynamic situation is always uncertain and unpredictable.
• Interest : Professor Mehta has defined interest as the earning of capital, which is determined by marginal productivity. The income of capital is determined by the productivity of the last unit of capital in use. Capital is supplied by available supply. The available capital is obtained from the cost of construction, or from direct cost.
• Rent : Professor Mehta has not considered the rent as income. According to him, it is a surcharge over the investment. In the vision of Mehta, when a production study is brought in only one specific use, then all income nature is a surcharge to it. According to him, it is impossible that an instrument is used only in one particular form in its absolute form. The more the quality of specificity of a resource, the more will be the rent received for it.