Understanding Average Propensity to Save (APS)

Average Propensity to Save (APS) is an important concept in macroeconomics. It measures the proportion of total income that is saved by households. It is calculated by dividing total savings (S) by total income (Y).

The formula for Average Propensity to Save is:

Income (Y) is either consumed (C) or saved (S). This means that Income is equal to the sum of Consumption and Saving:

If we divide the equation $\text{Y} = \text{C} + \text{S}$ by Y (assuming Y > 0), we get:

Here, APC stands for Average Propensity to Consume, which is the proportion of income that is consumed ($\text{C} / \text{Y}$). The identity $\text{APC} + \text{APS} = 1$ shows the relationship between APS and APC. Since both APC and APS represent proportions of income, their values depend on the levels of consumption, saving, and income.

Exploring the Possible Values of APS

Let's consider the possible values that Average Propensity to Save (APS) can take:

• APS can be positive: This happens when savings (S) are positive. If you save some part of your income, APS > 0.
• APS can be zero: This happens when savings (S) are zero. If you spend all your income and save nothing, S = 0, so APS = S/Y = 0.
• APS can be negative: This happens when savings (S) are negative. Negative saving is called dissaving, which occurs when consumption (C) is greater than income (Y). To consume more than income, one must draw from past savings or borrow. If C > Y, then S = Y - C < 0, so APS = S/Y < 0. This typically happens at very low levels of income, where basic needs require spending more than current earnings.

Analyzing the Maximum Value of APS

Now let's think about the upper limit of Average Propensity to Save. The formula is $\text{APS} = \text{S} / \text{Y}$.

For APS to be high, savings (S) must be a large proportion of income (Y). The maximum possible value for savings derived from current income is when consumption is zero (C=0). In this extreme theoretical case, all income is saved:

If S = Y, then APS would be:

So, theoretically, APS can be equal to 1 (Unity) if all income is saved and consumption is zero.

Can APS be greater than Unity? For APS > 1, Savings (S) would have to be greater than Income (Y). From the identity $\text{Y} = \text{C} + \text{S}$, if S > Y, then C must be negative (C = Y - S < 0). Negative consumption is not economically meaningful in this context. Therefore, savings from current income cannot exceed income, meaning S cannot be greater than Y.

Thus, Average Propensity to Save (APS) cannot be more than Unity.

So, the possible range for APS is generally \( \text{APS} \leq 1 \) (it can also be negative). The theoretical maximum value is 1.

However, in typical economic scenarios, even at high levels of income, people usually consume *some* portion of their income to meet needs and wants. If we consider a scenario where consumption (C) is always positive (C > 0), then Savings (S) must always be less than Income (Y), because $\text{S} = \text{Y} - \text{C}$. If S < Y (and Y > 0), then $\text{S}/\text{Y}$ must be less than 1.

Under the assumption that some positive level of consumption always exists (perhaps for necessities), Average Propensity to Save would always be strictly less than Unity. In this context, the maximum value that APS approaches but does not reach is 1. Thus, the maximum value is described as Less than Unity.

Therefore, considering the practical context where consumption is typically positive, the maximum value of average propensity to save is Less than Unity.

Based on the reasoning that realistic consumption is always positive, leading to savings being less than income, the maximum value for Average Propensity to Save is Less than Unity.

Revision Table: Key Concepts

Additional Information on Saving and Consumption

The concepts of propensity to consume and save are fundamental in Keynesian economics, particularly in understanding aggregate demand. The relationship between income, consumption, and saving helps economists analyze how changes in income levels affect spending and saving patterns in an economy. While the theoretical maximum of APS is Unity (when all income is saved), real-world data often shows that total household saving as a proportion of total income remains below this value, reflecting the necessity and desire for consumption.

It's important to distinguish APS from Marginal Propensity to Save (MPS). MPS measures the change in saving resulting from a change in income \( (\Delta\text{S} / \Delta\text{Y}) \). Similarly, Marginal Propensity to Consume (MPC) is \( (\Delta\text{C} / \Delta\text{Y}) \). Just like APC + APS = 1, MPC + MPS = 1.