A randomized trial of mailed questionnaires versus telephone interviews: Response patterns in a survey
2007

Comparing Mailed Questionnaires and Telephone Interviews in Health Surveys

Sample size: 4000 publication Evidence: high

Author Information

Author(s): Feveile Helene, Olsen Ole, Hogh Annie

Primary Institution: National Research Centre for the Working Environment, Copenhagen, Denmark

Hypothesis

Does the mode of data collection (mailed questionnaires vs. telephone interviews) affect response patterns in health surveys?

Conclusion

The mode of data collection significantly influences how people report their health, with telephone interviews leading to more positive responses.

Supporting Evidence

  • Telephone respondents used extreme response categories more frequently than those who received mailed questionnaires.
  • The overall response rate was similar for both methods, but demographic differences were noted.
  • For health self-assessment items, significant differences in response patterns were found.

Takeaway

This study shows that how you ask people about their health can change their answers, with phone calls often getting better responses than mail.

Methodology

A stratified sample of 4,000 adults in Denmark was randomized to receive either mailed questionnaires or telephone interviews, and response patterns were analyzed.

Potential Biases

There was a differential nonresponse bias observed for age and gender.

Limitations

The study did not account for potential biases in responses due to the nature of the questions asked.

Participant Demographics

Adults aged 20-60 from Denmark, with a balanced representation of gender and age.

Statistical Information

P-Value

0.26

Statistical Significance

p<0.001

Digital Object Identifier (DOI)

10.1186/1471-2288-7-27

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