Topology of the Landline Telephone Sampling Frame

Based on a series of studies conducted by the authors during the past two years, it has been reported that the landline telephone sampling frame may no longer hold some of the properties based on which list-assisted Random Digit Dial (RDD) sampling methodology was developed. Among other fundamental changes, the digital transition of the telephone network infrastructure has undermined the relevance of the 100-series telephone number banks for construction of RDD sampling frames. Today, local telephone exchanges are not servo-mechanical in nature anymore and hence such banks no longer serve as physical building blocks for telephone number assignments. Consequently, telephone companies are now less systematic in their assignment of numbers to new customers, Tucker and Lepkowski (2008). With departure from the above AT&T-dominated structure and emergence of various innovations in the telecommunication industry, the landline telephone sampling frame has become subject to unfolding new realities. On the one hand, the residential density of the 100-series telephone banks has been changing, which is a manifestation of a series of interrelated factors. On the other hand, with the growing number of alternative providers of voice services there are emerging issues that have confounded the operational definitions that the RDD methodology has relied upon for frame construction and identification of residential landlines.