Price Elasticity
Price elasticity of demand measures how much the quantity demanded of a good changes in response to a change in its price. Formally:
If a 10% price increase causes a 20% drop in quantity demanded, the elasticity is -2.0 (the negative sign indicates the inverse relationship between price and demand). Economists typically discuss the absolute value: an elasticity greater than 1 is called elastic (demand is sensitive to price), less than 1 is inelastic (demand is relatively insensitive to price), and exactly 1 is unit elastic.
The practical consequence: raising the price of an elastic good reduces total revenue (the volume loss outweighs the price gain), while raising the price of an inelastic good increases total revenue (volume holds while price rises). This is why pricing strategy depends on understanding elasticity rather than simply choosing the highest price the market might bear.
What determines elasticity? Three factors dominate:
Substitutability. The more easily a buyer can switch to an alternative, the more elastic demand is. Gasoline has inelastic demand because there is no convenient substitute for powering a car. A particular brand of bottled water has highly elastic demand because a dozen alternatives sit on the same shelf. In digital markets, willingness to pay for content behind a paywall depends directly on whether the reader perceives free substitutes — making content differentiation a pricing problem, not just an editorial one.
Necessity versus luxury. Goods that buyers consider essential (insulin, rent, basic food) have inelastic demand — people buy them regardless of price changes. Discretionary goods (entertainment, premium subscriptions, restaurant meals) have more elastic demand. Most digital content subscriptions fall on the discretionary end, which is why small price increases can cause meaningful subscriber losses.
Time horizon. Demand is generally more elastic over longer periods because buyers have time to find alternatives or change habits. A 20% increase in gas prices reduces driving less in the first month than over the following year, as people adjust commutes, buy more efficient cars, or move closer to work.
Elasticity is not a fixed property of a good — it is a property of a good in a market context. The same article might have inelastic demand among financial professionals who need it for decisions (no substitute, high stakes) and highly elastic demand among casual readers (many free alternatives, low stakes). This is why segmented pricing — charging different prices to different customer segments — can increase total revenue: it captures willingness to pay from inelastic segments without losing volume in elastic ones.