Examples of longitudinal studies

• Panel studies
  • US Panel Study on Income (PSID), an influential and long-established example

  • the German Socio-economic Panel (GSOEP)

  • the European Community Household Panel (ECHP), coordinated by Eurostat

  • the Panel Study of Belgian Households (PSBH)

• Cohort studies
  • the National Child Development Study of persons born in 1958 (NCDS)

  • the British Cohort Study of persons born in 1970 (BCS70).

  • the Millenium Cohort Survey (underway)

• Retrospective studies
  • the UK Family and Working Lives Survey from 1994 (FWLS)

  • the influential German Life History Studies (GLHS).

• Linked administrative studies
  • Several Scandinavian countries link tax and social welfare records for research

  • the UK Census Longitudinal Study (ONS-LS) links information from three censuses with vital registration records to create anonymised longitudinal data for about 1 percent of the population over a 20-year period.

• Repeated cross-sectional surveys
  • Labour Force Survey, General Household Survey, Family Expenditure Survey, British Election Study, opinion polls, many others.

• Advantages of longitudinal over (repeated) cross-sectional data
  • Better insight into causality (luxury of post hoc, ergo propter hoc error)
  • Can track processes
  • Can relate prior intentions to observed behaviour
  • Observe trajectories (e.g., poverty dynamics, exposure to unemployment), true flows rather than net change
  • Can control for unobserved heterogeneity
• Disadvantages
  • More expensive and difficult to carry out
  • Less representative than contemporary samples; poorer population estimates

• Advantages of panel over other longitudinal formats
  • Regularly repeated interviews: relatively accurate fresh data
  • Broad and detailed data
• Disadvantages
  • Short span: it takes a long time before there are long panel runs
  • Incomplete histories
  • Panel conditioning
  • Attrition