“I Haven't Got a Clue!?” Do Clueless Respondents Affect Data Quality through Response Behaviour?
However, if the “DK-option” is missing, respondents may skip the question and increase items missing. Offering a middle category in rating scales may even enlarge biases if perceived as “neither-nor-option”. In this connection personal characteristics and the type of question (e.g. opinion, attitude or behaviour) are expected to influence corresponding ad hoc decisions.
According to these consideration, the paper
i) focuses on the effect of different numbers of categories in combination with “don’t-know-options” on missing values,
ii) takes several question types into account and
iii) considers effects of personal characteristics on scale quality.
The results are based on methodical experiments included in three online surveys in Austria and Germany.
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