In the U.S. in the first half of 2009, 22.7% of households had only wireless telephones. Another 14.7% of households received all or almost all calls on a wireless phone. The share of wireless-only households has increased 2.5 percentage points in only six months.[1]
More rapid shift to wireless telephony among younger persons isn’t surprising. Among persons ages 25-29, a total of 64% lived in wireless-only or wireless-mostly households in the first half of 2009. Young persons do not want a shared phone. They are unlikely to shift back to a shared (wireline) phone as they get older.
Large differences in the share of wireless households across states are more difficult to understand. Some impressive statistical work constructed state-level estimates for wireless households in 2007. This work found “great variation in the prevalence of wireless-only households across states … ranging from a low of 5.1% in Vermont to a high of 26.2% in Oklahoma.”[2]
Differences in state demographics, household characteristics, and wireless subscribership per capita apparently don’t explain considerable variation across states. A logistic regression of wireless-only/wireline-phone-present households controlled for age, sex, race/ethnicity, household poverty status, home ownership status, other demographics, and state-level wireless subscribership per capita.[3] State-level wireless subscribership per capita was identified by its variation across 2007 within states. Within this regression, state fixed effects vary considerably. For example, Texas had a 16 percent point higher wireless-only household share than California would have at Texas’ levels of the control variables.[4] Wireless telephony is not regulated at the state level, but wireline telephony has been regulated at the state level since its beginnings. Perhaps some of the state-level variation in wireless-only households reflects state-level variation in wireline-phone offerings.
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Data: U.S. state-level data on wireless-only household, wireless subscribers, and households with wireline or wireless telephone service (Excel version).
Notes:
[1] Blumberg SJ, Luke JV. Wireless substitution: Early release of estimates from the National Health Interview Survey, January-June 2009. National Center for Health Statistics. December 2009. Available from: http://www.cdc.gov/nchs/nhis.htm
[2] Blumberg SJ, Luke JV, Davidson G, Davern ME, Yu T, Soderberg K. Wireless substitution: State-level estimates from the National Health Interview Survey, January-December 2007. National health statistics report; no 14. Hyattsville, MD: National Center for Health Statistics. 2009, p. 2.
[3] Id., Table II.
[4] For my calculation of the significance of the state fixed effects, see the state factor worksheet.