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Volume 16, Number 11—November 2010

Dispatch

Comparison of Survey Methods in Norovirus Outbreak Investigation, Oregon, USA, 2009

John Y. OhComments to Author , June E. Bancroft, Margaret C. Cunningham, William E. Keene, Sheryl B. Lyss, Paul R. Cieslak, and Katrina Hedberg
Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA (J.Y. Oh, S.B. Lyss); Oregon Public Health Division, Portland, Oregon, USA (J.Y. Oh, J.E. Bancroft, M.C. Cunningham, W.E. Keene, P.R. Cieslak, K. Hedberg)

Main Article

Table 1

Comparison of Internet- and telephone-based survey responses among participants of September 2009 bicycle ride, Oregon, USA*

Survey response No. respondents/total no. participants (%)†
Ratio (95% CI)
Internet-based survey Telephone survey
Initiation of survey 153/201 (76) 76/91 (84) 0.9 (0.8–1.02)
Confirmed ride participation 137/153 (90) 72/76 (95) 0.9 (0.9–1.02)
Completed survey 129/137 (94) 72/72 (100) 0.9 (0.9–0.98)
Overall completion rate 129/201 (64) 72/91 (79) 0.8 (0.9–0.98)
Completed surveys within 2 days after survey release 92/129 (71) 47/72 (65) 1.1 (0.9–1.3)
Answered 90% of questions about food items 74/129 (57) 68/72 (94) 0.6 (0.5–0.7)
Attack rates‡ 23/126 (18) 13/72 (18) 1.0 (0.5–1.9)

*CI, confidence interval.
†Number of riders who answered the question compared with number of riders who were asked.
‡Three respondents to the Internet-based survey who reported illness that did not meet the case definition were excluded from analysis for attack rates.

Main Article

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