Extended field efforts to reduce the risk of non-response bias: have the effects changed over time? Can weighting achieve the same effects?
Mode-switch protocols: how a seemingly small design difference can affect attrition rates and attrition bias
Mode-switch protocols: how a seemingly small design difference can affect attrition rates and attrition bias
Causes of mode effects: separating out interviewer and stimulus effects in comparisons of face-to-face and telephone surveys
Effects of visual and aural communication of categorical response options on answers to survey questions