List-Assisted RDD Sampling in Korea: Testing the Feasibility of National Survey Under Within-Household Selection

In spite of the changing environment in telephone surveys due to the recent increase of households with cell phones only, landline phone frames in many countries still play an important role in their sample designs to select representative populations. The studies on random digit dialing (RDD) landline frames, which were much influenced by the past developments of RDD sampling methods in the United States, have been conducted in some countries including the UK and Germany. However, RDD sampling methods have not reached the levels of use in the United States (Kalsbeek and Agans, 2008). In Korea, landline phone directory sampling has been mainly used to select samples of telephone households in social surveys or research for public policy as well as electoral polls. Until the mid-2000s, printed landline phone directories were used as official sampling frames because of a set of regulations designed to protect the private information of subscribers. Since then a commercial firm has begun providing elec-tronic telephone directories, and many survey research companies have used them to build their own databases of landline numbers to be used as national sampling frames.