Elasticity is a measure of the responsiveness of demand (or supply) to a change in price, income, or other factor. The coefficient of elasticity calculated by the dividing percentage change in the quantity demanded by the percentage change in price or other driving factor. Price elasticity is normally negative as price and demand are inversely related to each other, while income elasticity is normally positive. Ignoring the negative sign of the elasticity coefficient, demand is elastic when the coefficient is greater than 1. Demand is inelastic when the coefficient is less than 1.