Mixed mode designs are increasingly important in surveys and large longitudinal studies are progressively moving to or considering such a design. In this context our knowledge regarding the impact of mixing modes on data quality indicators in longitudinal studies is sparse. This study tries to...

Using multiple modes to collect data is becoming a standard practice in survey agencies. While this should save costs and decrease non-response error it may have detrimental effects on measurement quality. This can happen because different modes have distinct measurement biases which, when...