Outbreak Investigation: Internet vs Telephone Inteviews?

There is an interesting report out in the November EID by Johns Oh and colleagues in Oregon.  During a 475-mile bike ride in fall 2009, six riders reported a GI illness that was confirmed as norovirus.  To obtain additional information from other riders, Oregon Public Health officials identified the 1,288 riders who were Oregon residents and administered a 95-item survey using one of two methods at random.  204 completed the survey over the internet and 93 over the telephone (it took me a minute to remember what a telephone was...)

The findings were a bit surprising.  While a similar percent initiated the survey, 76% internet vs 84% telephone, only 64% completed the survey on the internet vs 79% who completed it on the phone, p=0.01. Internet responders were much less likely to complete the food item questionnaire (57% vs 94% on the telephone). What was most surprising is that older riders >50yo completed the internet survey much more often compared to those <50yo (70% vs 56%, p=0.05).  I guess the internet is distracting especially to young people. Who won the World Series again and what's the weather like outside? I'm sure older riders were more likely to have window offices and thus didn't need the internet to answer that last question.  One caveat that the authors made is that the findings in this study might not be generalizable to lower socioeconomic groups with low levels of internet access - for example 201 of 204 riders in the internet survey had valid email addresses; this is likely higher than the general population.

Oh JY et al. EID November 2010

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