Cellular Telephone, New Products and the CPI
NBER Working Paper No. 5982
Cellular telephone is an example of a new product that has significantly affected how Americans live. Since their introduction in 1983, cellular telephone adoption has grown at 25-35% per year such that at year end 1996 about 42 million cellular telephones are in use in the U.S. However, cellular telephone has not been included in the construction of the CPI, and the CPI will not include cellular telephone until 1998 or 1999. This neglect of new goods leads to an upward bias in the CPI. The analysis of the paper demonstrates that the gains in consumer welfare from a new product such as cellular telephone can be substantial. The paper also gives an approximation result which the BLS could use to calculate gains in consumer welfare from new products for use in the CPI. The BLS telecommunications CPI estimates that since 1988, telecommunications prices have increased by 8.5% or an increase of 1.02% per year. This estimate ignores cellular service. A corrected telecommunication services COLI that includes cellular service decreased from 1.0 in 1988 to 0.903 in 1996 for a decrease of 1.28% per year. Thus, the bias in the BLS telecommunications services CPI equals approximately 2.3 percentage points per year. The neglect of new products in the CPI can lead to significant biases.
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Published: JBES, Vol. 17, no. 2 (April 1999): 188-194.