title: Use of a Google Map Tool Embedded in an Internet Survey Instrument: Is it a Valid and Reliable Alternative to Geocoded Address Data?
abstract: BACKGROUND
  Men who have sex with men (MSM) in the United States are at high risk for human immunodeficiency virus (HIV) and poor HIV related outcomes. Maps can be used to identify, quantify, and address gaps in access to HIV care among HIV-positive MSM, and tailor intervention programs based on the needs of patients being served.
  
  
  OBJECTIVE
  The objective of our study was to assess the usability of a Google map question embedded in a Web-based survey among Atlanta-based, HIV-positive MSM, and determine whether it is a valid and reliable alternative to collection of address-based data on residence and last HIV care provider.
  
  
  METHODS
  Atlanta-based HIV-positive MSM were recruited through Facebook and from two ongoing studies recruiting primarily through venue-based sampling or peer referral (VBPR). Participants were asked to identify the locations of their residence and last attended HIV care provider using two methods: (1) by entering the street address (gold standard), and (2) "clicking" on the locations using an embedded Google map. Home and provider addresses were geocoded, mapped, and compared with home and provider locations from clicked map points to assess validity. Provider location error values were plotted against home location error values, and a kappa statistic was computed to assess agreement in degree of error in identifying residential location versus provider location.
  
  
  RESULTS
  The median home location error across all participants was 0.65 miles (interquartile range, IQR, 0.10, 2.5 miles), and was lower among Facebook participants (P<.001), whites (P<.001), and those reporting higher annual household income (P=.04). Median home location error was lower, although not statistically significantly, among older men (P=.08) and those with higher educational attainment (P=.05). The median provider location error was 0.32 miles (IQR, 0.12, 1.2 miles), and did not vary significantly by age, recruitment method, race, income, or level of educational attainment. Overall, the kappa was 0.20, indicating poor agreement between the two error measures. However, those recruited through Facebook had a greater level of agreement (κ=0.30) than those recruited through VBPR methods (κ=0.16), demonstrating a greater level of consistency in using the map question to identify home and provider locations for Facebook-recruited individuals.
  
  
  CONCLUSIONS
  Most participants were able to click within 1 mile of their home address and their provider's office, and were not always able to identify the locations on a map consistently, although some differences were observed across recruitment methods. This map tool may serve as the basis of a valid and reliable tool to identify residence and HIV provider location in the absence of geocoded address data. Further work is needed to improve and compare map tool usability with the results from this study.
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States. sdasgu4@emory.edu.
authors.forename: Sharoda
authors.initials: S
authors.lastname: Dasgupta
authors.forename: Adam S
authors.initials: AS
authors.lastname: Vaughan
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kramer
authors.forename: Travis H
authors.initials: TH
authors.lastname: Sanchez
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Sullivan
keywords: HIV; geographic mapping; reliability; survey; validity
references.citation: Spat Spatiotemporal Epidemiol. 2012 Apr;3(1):69-82
references.pmid: 22469492
references.citation: Geospat Health. 2012 Nov;7(1):145-51
references.pmid: 23242688
references.citation: Am J Epidemiol. 2006 Feb 1;163(3):197-203
references.pmid: 16339049
references.citation: Am J Perinatol. 2014 Apr;31(4):287-92
references.pmid: 23765706
references.citation: J Nephrol. 2013 Jan-Feb;26(1):3-15
references.pmid: 23065915
references.citation: Sex Transm Infect. 2004 Aug;80(4):294-9
references.pmid: 15295129
references.citation: Am J Epidemiol. 2010 Dec 1;172(11):1292-8
references.pmid: 20880962
references.citation: Sex Transm Infect. 2007 Apr;83(2):113-9
references.pmid: 17005541
references.citation: AIDS Behav. 2010 Dec;14(6):1353-61
references.pmid: 20665100
references.citation: AIDS Behav. 2009 Jun;13(3):488-98
references.pmid: 19205866
references.citation: PLoS One. 2012;7(10):e46029
references.pmid: 23056227
references.citation: Am J Epidemiol. 2007 Dec 1;166(11):1345-54
references.pmid: 17728269
references.citation: Health Promot Pract. 2011 Jan;12(1):63-73
references.pmid: 19546198
references.citation: Fam Med. 2005 May;37(5):360-3
references.pmid: 15883903
references.citation: Sex Transm Dis. 2006 Sep;33(9):576-84
references.pmid: 16540884