`Continuous' longitudinal data

• Strict `panel' measurement is repeated-static in form
• Most panel surveys attempt to create continuous histories in some domains, including employment status
• This involves short and long term retrospective components
• `Panel' data is more complex than cross-sectional, in adding a dimension: rectangle becomes a 3D matrix
• Continuous representations are more complex in structure and in measurement error problems
• BHPS continuous measurements covers employment status and occupation, marriage and cohabitation, fertility inter alia