The advancement of information and communication technologies has greatly changed the lifestyle of people while using landline surveys in soliciting precise public opinion is becoming limited. As people use a variety of devices such as cellphones, internet phones and APPs in daily communication, problems of insufficient population coverage arise from relying only on landline phones to reach respondents. Therefore, a daunting task in the telephone polling industry is to ensure sample representation for obtaining precise population parameters. To achieve such an objective, a common practice by pollsters in Taiwan is to use household data as
weighting statistics. Many cases, however, have shown this practice to be inappropriate.
To solve the above-mentioned problem, this study proposes an estimation method based on a dual frame survey that combines landline phones and cellphones. We further use data from the 2016 presidential election to compare different estimations based on a dual frame survey. Our results demonstrate that a “landline survey supplemented by cellphoneonly” is the best combination, considering sample coverage and estimation error. The second-best alternatives are “cellphone survey supplemented by landline-only” and “use both landline and cellphone.” In other words, “the most economical and efficient” strategy of a dual frame survey is to conduct a traditional landline survey and incorporating cellphone-only respondents. The data collected in such combination not only reflect the characteristics of the population, but also cost much less than other strategies.