Two-Price Market

Ian McCarthy | Emory University

Motivation

In health care, providers usually face two prices:

  1. A price fixed by Medicare and Medicaid, \(p_{m}\).
  2. A price that is negotiated with insurers, \(p_{n}\).

How does \(p_{m}\) affect \(p_{n}\)?

Profit maximizing hospital

Two price market and FP

Because the hospital is a profit maximizing firm, it will choose the quantity that maximizes profits, \(q^{*}\), where:

  • Sell to “private” market as long as marginal revenue exceeds the public price
  • Switch to “public’” market otherwise, and sell to the point where price equals marginal cost

Two-price market in pictures

In-class problem (two-price market)

Consider the firm’s demand curve in the private insurance market, \(d=16-q\), and costs, \(c(q)=5+q^{2}\). Assume that there exists a public insurer that pays a fixed price of \(\bar{p}=10\).

  1. How many private patients will the provider serve?
  2. How many public patients?
  3. What if \(\bar{p}\) drops to $9.

Not-for-profit objectives

Two price market and NFP

Although we don’t know the general solution for the private price, we can find how it varies with the public price…

\[\frac{\mathrm{d}p_{i}}{\mathrm{d}p_{j}} = - \frac{U_{11}\pi_{1}^{i}\pi_{1}^{j} + \frac{\mathrm{d}D_{i}}{\mathrm{d}p_{i}}U_{12}\pi_{1}^{j}}{\frac{\mathrm{d}^{2}U}{\mathrm{d}p_{i}^{2}}}\]

Cost-shifting

  • Relationship between public and private price is important
  • Speaks to anticipated effects of a change in Medicaid or Medicare rates
  • Do hospitals “make up” the difference?

The idea that hospitals will increase private prices following a decrease in the public price is called cost shifting.

How does cost-shifting work?

Assumes that hospitals could have increased private prices earlier but chose not too. This is technically possible if, for example:

  • Hospital has very low margins (maybe negative with a lower public price)
  • Insurer wants to prop up the hospital for competitive reasons
  • Hospital has diminishing returns to profits

but economists usually see this as a smaller effect than most policy makers