The Definition of Income, Saving and Investment
4 minutes • 752 words
Table of contents
Here are my definitions:
Sales
is an entrepreneur’s income from a sale of a productPurchases
is his expense in buying that product from his supplierAssets
is his expense for capital equipment- This includes his unfinished goods (working capital) and finished goods
Maintenance
is the cost of maintaining the assets
My equations are:
Depreciated Asset Value = Asset - Maintenance
Gross Sales + Assets - Purchases
Some part, however, of Gross Sales
will be attributable to the capital equipment which he had at the start.
The income of the current period is obtained by deducting from A + G - A1
a certain sum, to represent that part of its value which has been contributed by the equipment inherited from the previous period.
The problem of defining income is solved as soon as we have found a satisfactory method for calculating this deduction.
There are 2 possible principles for calculating it:
- In connection with production
- In connection with consumption
Income Defined by Production
(i) The actual value Assets
is the net result of the cost of maintaining and depreciating it.
This cost is Maintenance
. Therefore:
Depreciated Asset Value = Asset - Maintenance
Savings = Depreciated Asset Value -
The excess of this potential value of the equipment over Assets - Purchases
is the measure of what has been sacrificed (one way or another) to produce Sales
.
This is the User Cost
[1]
The user cost of Sales
is Depreciated Asset Value - B’ - Asset - Purchases
(G' - B') - (G - A1)
- This measures the sacrifice of value involved in the production of
Sales
The factor cost of Sales
is the amount paid out by the entrepreneur to the other factors of production.
The prime cost of the output Sales
is the sum of the Factor Cost
and the User Cost
.
The income[2] of the entrepreneur is the excess of the value of his finished output sold over his prime cost.
- This depends on his scale of production which he wants to maximise, i.e., to his gross profit
The income of the rest of the community is equal to the entrepreneur’s factor cost.
Aggregate income = Sales - User Cost
Income therefore is a completely unambiguous quantity.
The entrepreneur expects profits.
- He endeavours to maximise those profits.
- From this, he decides how much employment to give
Assets - Purchases
might exceed Depreciated Value - B'
so that user cost will be negative.
For example, this might be the case:
- if we choose our period in such a way that input has been increasing during the period but without there having been time for the increased output to reach the stage of being finished and sold.
- whenever there is positive investment, if we imagine industry to be so much integrated that entrepreneurs make most of their equipment for themselves.
User Cost
is only negative when the entrepreneur has been increasing his capital equipment by his own labour.
- This is usually positive.
Marginal User Cost
associated with an increase in Sales
is dUser_Cost / dSales
- This will be negative
For society as a whole:
Aggregate Consumption = Summation of Sales - Summation of Purchases
Aggregate Investment = Summation of Purchases - User Cost
is equal to
User Cost
is the individual entrepreneur’s disinvestment
-User Cost
is his investment in terms of his own assets.
-User Cost = Assets - ()
A completely vertically integrated system has Purchases = 0
- Its
Consumption = Sales
- Its `Investment = -User Cost
The introduction of complicates the above.
The effective demand is simply the gross income which the entrepreneurs expect to receive.
- This includes the incomes which they will hand on to other factors of production, from the amount of current employment.
The aggregate demand curve is the hypothetical quantity of employment related to the income from their outputs.
The effective demand is the point on the aggregate demand curve which corresponds to the level of employment which maximises the entrepreneur’s expectation of profit*.
Superphysics Note
From here, we can equate the marginal income to the marginal factor cost.
- This leads to the same propositions relating marginal income to marginal factor costs.
- This ignores user cost or assumes it to be 0.
- In this way, they have equated supply price[3] to marginal factor cost.[4]