David Landau, CFA, was discussing the biases associated with the Consumer Price Index (CPI). He was also discussing the effect of these biases on determining the inflation rate of an economy. Which of the following is least likely a source of bias in CPI data and does the CPI generally understate or overstate the true rate of inflationNot a source of biasCPI bias direction（）
A. Outlet substitution Overstate
B. Quality changes Understate
C. Consumer preferences Overstate
参考答案：C
解析：
The four sources of bias associated with CPI data are: new goods, quality changes, commodity substitution, and outlet substitution. As a result, in 1996 a Congressional Advisory Commission concluded that the CPI tends to overstate the true rate of inflation by 1.1% per year.