The population covered by the MCPI and the overall CPI is the same.
The difference between hospital list prices (typically the charge to a full-paying patient) and the prices hospitals actually receive has been a major source of bias for the MCPI.
The different between list and transactions prices has increased.
List prices increased faster than actual prices.
A large part of the price is paid out of pocket.
An important factor affecting the weight of the MCPI is the exclusion of services that are paid for by the government (Medicare and Medicaid) and employer contributions to health insurance policies for their employees.