## Introduction to Elasticity

Read this chapter to learn about the concept of elasticity. Be sure to read all the sections in this chapter (Sections 5.1-5.4) following the introduction.

### 5.4 Elasticity in Areas Other Than Price

#### Elasticity in Labor and Financial Capital Markets

The concept of elasticity applies to any market, not just markets for goods and services. In the labor market, for example, the wage elasticity of labor supply ­– that is, the percentage change in hours worked divided by the percentage change in wages ­– will determine the shape of the labor supply curve. Specifically:

$\text { Elasticity of labor supply }=\frac{\% \text { change in quantity of labor supplied }}{\% \text { change in wage }}$

The wage elasticity of labor supply for teenage workers is generally thought to be fairly elastic: that is, a certain percentage change in wages will lead to a larger percentage change in the quantity of hours worked. Conversely, the wage elasticity of labor supply for adult workers in their thirties and forties is thought to be fairly inelastic. When wages move up or down by a certain percentage amount, the quantity of hours that adults in their prime earning years are willing to supply changes but by a lesser percentage amount.

In markets for financial capital, the elasticity of savings ­– that is, the percentage change in the quantity of savings divided by the percentage change in interest rates ­– will describe the shape of the supply curve for financial capital. That is:

$\text { Elasticity of savings }=\frac{\% \text { change in quantity of financial savings }}{\% \text { change in interest rate }}$

Sometimes laws are proposed that seek to increase the quantity of savings by offering tax breaks so that the return on savings is higher. Such a policy will increase the quantity if the supply curve for financial capital is elastic, because then a given percentage increase in the return to savings will cause a higher percentage increase in the quantity of savings. However, if the supply curve for financial capital is highly inelastic, then a percentage increase in the return to savings will cause only a small increase in the quantity of savings. The evidence on the supply curve of financial capital is controversial but, at least in the short run, the elasticity of savings with respect to the interest rate appears fairly inelastic.