| 1. |
- Bälter, Olle, 1962-, et al.
(author)
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Demands on web survey tools for epidemiological research
- 2005
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In: European Journal of Epidemiology. - Karolinska Inst, Dept Med Epidemiol & Biostat, Stockholm, Sweden. : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 20:2, s. 137-139
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Journal article (peer-reviewed)abstract
- In countries where the Internet access is high, a web-based questionnaire could save time and money compared to printed questionnaires, mainly by eliminating the two steps of transferring answers from printed to a digital data set and manually completing missing and impossible answers. However, many of the features wanted for conducting large epidemiological studies are not available in many web survey systems. Here we describe design issues the investigator needs to be aware of when using web-based questionnaires in epidemiological research.
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| 2. |
- Lagerros, Y. T., et al.
(author)
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Validity and reliability of self-reported total energy expenditure using a novel instrument
- 2006
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In: European Journal of Epidemiology. - Karolinska Inst, Dept Med Epidemiol & Biostat, SE-17177 Stockholm, Sweden. Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA. Univ Milano Bicocca, Dept Stat, Milan, Italy. Royal Inst Technol, Sch Comp Sci & Commun, Stockholm, Sweden. : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 21:3, s. 227-236
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Journal article (peer-reviewed)abstract
- Improved methods for quantitative self-reports of total physical activity in epidemiological studies are needed. We evaluated randomly selected individuals' ability to integrate their perception of physical activity over time to produce an estimate of the usual level, using a novel instrument for self-quantification of energy expenditure. A population-based sample of 418 Swedish men and women, age 20-59, completed a questionnaire containing the new instrument. For validation, three 24 hour recalls by phone served as gold standard. Reproducibility was assessed through administering the instrument another three times. The validation involved 133 subjects and another 160 completed the reproducibility evaluation. Pearson correlation between usual daily energy expenditure measured by the instrument and the mean of the 24 hour recalls was 0.73. After subdividing the self-reported daily energy expenditure and the mean of the 24 hour recalls into quintiles, 83.5% of the participants remained in the same quintile, or one quintile apart. There was a tendency towards overestimation of usual daily physical activity. This was significantly associated with low education. Reproducibility showed an intraclass correlation of 0.55. Although integrated reports of usual daily energy expenditure over longer periods seem to be afflicted with a tendency of overestimation, total energy expenditure can be estimated with reasonable validity and reproducibility using our instrument.
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