Mohammed T. Abou-Saleh

LONG-TERM OUTCOME STUDIES OF PSYCHIATRIC DISORDERS 107crisscross (or reverse) directory, which lists telephone numbers byaddress.The Internet serves as an effective and cost efficient method oflocating absent subjects. Various websites contain an extensiveamount of information regarding residential listings. Internetsources differ by the type of information required to perform asearch. When utilizing online databases, Smith and Watts 27suggest that: ‘‘It is important that the investigator try each sourcebefore moving on to the next site. Failure to locate a number onone site does not mean that a search of another site will befruitless’’ (p. 434). Some examples of current websites include:www.infoseek.comwww.semaphorecorp.comwww.databaseamerica.comwww.four11.comwww.yahoo.com/reference/whitepageswww.angelfire.comwww.yahoo.com/search/peoplewww.switchboard.comwww.whowhere.comwww.lookupusa.comThe Department of Motor Vehicles can provide usefulinformation on an individual, including one’s address, date ofbirth and social security number, and can select physicalcharacteristics; however, investigators must be cognizant ofstate-specific limitations and restrictions on public access toinformation. Similarly, voter registration files are restricted incertain states, yet careful review of files, when available, canproduce useful information.TRW, TRANSUNION and EQUIFAX, the nation’s majorcredit bureaux, can provide vital information on patients, such ascurrent and previous addresses, social security number, birth date,employer and spouse’s name. Each of these credit-reportingservices offers affordable products for assessing patient status.TRW offers TRW Social Search and TRW Address Update.Transunion offers TRACE, TRACEplus, ReTRACE and theATLAS. Equifax offers DTEC and ID REPORT. Each productcan successfully provide essential data but differs by the specificinformation generated and what is required for initiation of asearch. Utilization of these credit bureaux is legal, offeringcomprehensive, affordable, time- and cost-efficient means forlocating patients.Information brokers may also be of use in attempting to locatemissing subjects. Information brokers have access to variedsources of information, yet are typically costly options. As aresult, it is recommended that researchers assess the necessity tolocate their subjects prior to selecting such alternatives 27,29 .Similar sources of information may be available outside the USA.Sources for Locating Patients Assumed DeceasedVarious services are available for locating individuals who arebelieved to be dead. The National Death Index (NDI) identifiesthe states in which death occurred, the corresponding deathcertificate number and the date of death. The NDI file providesinformation for all 50 states, the District of Columbia, PuertoRico and the Virgin Islands. The NDI database is updatedannually and begins with deaths occurring in 1979.NDI users can apply for NDIplus, an optional service that, inaddition to the aforementioned information, provides details onthe underlying and multiple causes of death for deceased patients.Procedures for requesting information through NDI vary by state.Prospective NDI and NDIplus users must submit an applicationform to the National Center for Health Statistics. Informationregarding NDI and NDIplus can be obtained by contacting:National Center for Health Statistics, Centers for Disease Controland Prevention, 6525 Belcrest Road, Room 820, Hyatsville, MD20782-2003, USA.Tel: (301) 436-8951, ext 109 or 101; fax: (301) 436-7066: e-mail:ROB3@CDC.GOVThe Equifax Nationwide Death Search provides information ondeaths since 1955 from data compiled from the Social SecurityAdministration. Search results will produce birthdate, date ofdeath and state and zip code at death. Equifax is updatedcontinuously and is therefore recommended for obtaining dataregarding recent deaths. Furthermore, because records areavailable beginning in 1955, Equifax is potentially more usefulfor some retrospective cohort designs than the NDI 28 .Other sources for identifying deceased subjects include theDeath Master File from the Social Security Index 27,29 . Thisinformation can be accessed at www.ancestry.com.Contact information for additional services includes:Social Security Administration’s Death Master File, US Departmentof Commerce, Technology Administration, 5285 Port RoyalRoad, Springfield, VA 22161, USA.Tel: (703) 487-4630Equifax Credit Information Services, PO Box 105835, Atlanta,GA 30348-5835, USA.Tel: (800) 944-6000Trans Union Corporation, PO Box 8309 File 99506, Philadelphia,PA 19101-8309, USA.Tel: (610) 690-3126CONCLUSIONSLong-term follow-up studies provide a useful vehicle forinvestigating stability and change in the course and consequencesof psychiatric disorders; they raise a number of methodologicaland practical considerations as well. In this chapter we have triedto highlight basic methodological issues and practical approachesthat bear on the interpretation and comparison of researchfindings and to reference practice approach and texts that addressthe issues in greater detail.REFERENCES1. 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