Cellular-Only Substitution in the United States as Lifestyle Adoption: Implications for Telephone Survey Coverage

Historically, the coverage bias from excluding the United Statescell-only population from survey samples has been minimal dueto the relatively small size of this group. However, the unrelentinggrowth of this segment has sparked growing concern that telephonesurveys of the general public in the United States will becomeincreasingly subject to coverage bias. While there is evidencethat demographic weighting can be used to eliminate this bias,the availability of the weights lag behind the rapidly changingcell-only population. To explain the extent of the problem,we propose a reliable model to forecast cell-only populationsize and demographics. This model posits that a stable behavioralprocess, the rate of habit retention, can be estimated fromprior wireless lifestyle adoption in the United States and mayalso describe adoption of the cell-only lifestyle. Using measuresof incentive and habituation, we test this assumption by predictingchanges in the cell-only population size and changes in agedemographics. The accuracy of predictions confirms the two adoptionbehaviors are similar. We then develop forecasts of age demographicsthrough 2009, and show how cell-only lifestyle adoption leadsto potential coverage bias that is better addressed throughthis type of modeling rather than weighting from historicaldata.