成本考量下雙底冊電話調查的樣本配置

Allocation of Dual-Frame Telephone Survey for Given Cost

近年來，隨著唯手機族日增，傳統住宅電話調查面臨了涵蓋率不足的問題，執行手機與住宅電話的雙底冊電話調查便成了必要之舉。進行雙底冊電話調查需要決定樣本如何配置，而配置方式又與權數效應和調查成本有關。準此，本研究依據既有成本比較研究中手機與住宅電話樣本每單位完訪成本比，以及從「數位國情調查」的雙底冊電話調查結果所估計出來的權數效應，試著在調查成本固定的情況下，找出權數效應最小，也就是有效樣本規模最大，讓估計精確性最佳的手機與住宅電話樣本配置。結果顯示，在最常見的住宅電話加上唯手機族之雙底冊電話調查中應配置64.18％的住宅電話以及35.82％的唯手機族樣本。此外，本研究還進一步將此類雙底冊電話調查的樣本配置通式化，使得唯手機族的樣本數成為調查成本與電話使用習慣的函數，讓研究者在規劃這類的雙底冊電話調查時，可依不同的情況代入相關參數後得到有效樣本規模最大的樣本配置。 With the increase of cell phone usage in recent years, traditional landline surveys face a problem of incomplete coverage. It is now necessary to conduct dual-frame telephone surveys that includes cell phone samples and landline samples. Designing a dual-frame telephone survey requires a decision on the sample allocation. The allocation of the sample to the dual-frame associates with the unequal weighting effect and the survey cost. Therefore, this study aimed to illustrate an optimal allocation of respondents from landline and cellphone frames that result in the lowest unequal weight effect (i.e., the highest effective sample size) for a given cost by using the relative unit cost of obtaining a cell respondent compared to a landline respondent from a comparison study of survey cost, and an unequal weighting effect from “Public Value and Electronic Governance.” The results suggested that the optimal design will have 64.18% of the sample completes from the landline frame, and 35.82% of the sample completes from the cellphone frame in a cell-phone-only screened design. Additionally, this paper shows that the sample sizes of cell phone only could be a function of unequal weight effect and survey cost. Thus, the organizer of the cell-phoneonly screened design could substitute parameters into the function depending on different situations.