Abstract:
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Non-ignorable nonresponse occurs when the reason for not responding to a survey directly relates to the outcome of interest. This source of bias cannot be addressed through standard weighting adjustments that rely on auxiliary variables. The Programme for the International Assessment of Adult Competencies (PIAAC) administers adult skills assessments (e.g., literacy, numeracy) in a country's main language(s). It is subject to non-ignorable nonresponse because of persons that are unable participate due to a language barrier, learning/mental disability, or reading/writing barrier. This paper provides background on the extent of literacy-related nonresponse across the participating countries, the implications of treating such cases as missing at random, and the handling of such cases in weighting and estimation for the first cycle of PIAAC. It then describes plans to reduce the extent of potential bias due to literacy-related nonresponse in the second cycle by introducing a brief multi-lingual questionnaire called the Doorstep Interview.
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