What is the Significance of cross elasticity in business decision making?

The degree of change in the demand for one product as a response to a change in the price of a different product. For example, an increase in the price of petroleum is likely to have a negative impact on the demand for gas-guzzling vehicles and a positive impact on the demand for fuel-efficient vehicles. The cross elasticity for substitutes is generally positive, in that a price increase for one product will result in an increase in demand for a substitute.