This example shows that economic theory alone may not be able to predict the sign of an elasticity and that
elasticity coefficients need to be estimated from data on consumer behavior.
The differences in health care elasticities for overall primary care (–0.1 to –0.7)
and for services provided by individual physicians (–2.80 to –5.07) again illustrate
the principle that demand can be much more elastic for the individual producer
of a product than for the product in general. Although these differences between
product and individual producer elasticities are not as large as those between agricultural
products and their producers, they still indicate that individual physicians
are considered substitutes for one another.