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Procedures and Measures for Further Research 65 even if that means that it is not necessarily interviewer-friendly. Personalized interviewing tech- niques are also becoming increasingly popular through travel behavior modification programs such as TravelSmart and Travel Blending. As part of NCHRP Project 8-37, Westat undertook a pilot study of a modified version of the Brg interviewing technique on a sub-sample of around 100 households participating in the 2002 wave of the Metropolitan Washington DC Council of Governments Longitudinal Household Travel Survey (COG LHTS) (Freedman and Machado, 2003) (see Section 5.1 of the Technical Appendix). In this CATI survey, a three-person team of interviewers was assigned to each house- hold through its participation period. This approach was adopted to establish a high level of rap- port between interviewers and participants and to create a situation where respondents would feel comfortable to call interviewers at any time during the daily interview hours (Freedman and Machado, 2003). Although it was found that the procedures adopted in the study showed prom- ise, operational difficulties made it difficult to make any firm conclusions regarding the effective- ness of the method (Freedman and Machado, 2003). It is recommended that more work be done to evaluate the effectiveness of the Brg method. The test undertaken by Westat, while useful, was limited by constraints imposed by the COG LHTS of which it was a part. It is suggested that in future work, the method be tested in a stand alone survey. 4.3.4 Geocoding Methods A number of general standards relating to geocoding were recommended in this project (see Sections 8.1 and 8.2 of the Technical Appendix). However, there is further work that can be done. The success of geocoding data depends on three issues: the quality of reference data (address infor- mation stored in GIS); the quality of target data (addresses reported by respondents); and the method adopted to match addresses. The limitations of reference data have been well documented (Greaves, 1998 and 2003), as have the problems that respondents have in accurately reporting addresses (Stopher and Metcalf, 1996). However, very little work has been done to evaluate the effectiveness of different techniques that can be used for dealing with partial matches (e.g., crite- ria relaxation and scoring-based systems). While Drummond (1995) provided a general overview of geocoding techniques, it is largely unknown what approach produces the best results. Also, decisions about what soundex score should be accepted or the extent to which matching criteria should be relaxed are generally very subjective. In future research, it is recommended that geocod- ing be performed on a number of common data set using a variety of different GIS packages. In addition, a more thorough evaluation could also be conducted of systems capable of geocod- ing in real time. In this project, it was not possible to do any meaningful analysis of the costs and benefits associated with real-time geocoding. Anecdotal evidence suggests that significant improvements can be made when reported addresses can be instantaneously validated and cross- checked during the interview process through specialized CATI systems that incorporate address gazetteers (for schools, shopping malls, and other commonly visited locations). Although such systems have now been used in a substantial number of surveys, it is difficult to quantify the ben- efits of the technology because of the difficulties in comparing different types of surveys and dif- ferent CATI systems. However, with a more detailed review of these surveys, it would be possible to at least determine what types of addresses can be included on online gazetteers. 4.3.5 Impacts of the National Do Not Call Registry The National Do Not Call Registry was set up to protect households from being bombarded with telemarketing calls. It would be useful to know whether this has had a positive impact on the recruit- ment rates to household travel surveys. If so, then survey firms would need to draw smaller samples than in the past, and this would represent a cost saving in terms of the number of households that