Estimates of Biases by Type and in Total
Has quality change bias increased or decreased? Table 2 provides some insights to that issue. To take the specific example of 1980, we can aggregate the rates of bias given in Table 2 and come up with an upward CPI bias due to quality change and new products of0.488 percent per year, compared to 0.613 for 1996. The main differences come from the reversal of the previous down ward bias for apparel and the increased upward bias in the appliance/radio/ TV component due to the growing role of personal computers. Partially off setting these sources of increased upward bias are reductions in the extent of upward bias in used cars, airline fares, and prescription drugs.