[A comparison of two methods to adjust for non-response bias: field substitution and weighting non-response adjustments based on response propensity].

UNLABELLED

Unit non-response is a growing problem in sample surveys that can bias survey estimates if respondents and non-respondents differ systematically.

OBJECTIVES

To compare the results of two nonresponse adjustment methods: field substitution and weighting nonresponse adjustment based on response propensity.

METHODS

Field substitution and response propensity weights are used to adjust for non-response and their effect on the prevalence of six survey outcomes is compared.

RESULTS

Although significant differences are found between respondents and non-respondents, only slight changes on prevalence estimates are observed after adjustment, with both techniques showing similar results. In the sole case of smoking, substitution seems to have further biased survey estimates.

CONCLUSIONS

Our results suggest that when there is information available for both respondents and non-respondents, or if a careful sample substitution process is performed, weighting adjustments based on response propensity and field substitution produce comparable results on prevalence estimates.