ONS longitudinal study
\ɑnz\ \ˌlɑnʤəˈtudənəl\ \ˈstʌdi\
A longitudinal study of the England and Wales population run by the UK’s Office for National Statistics.
The Office for National Statistics (ONS) longitudinal study started in 1971 as a means of understanding trends within the England & Wales population. Everyone born on one of four specific days in the year is traced between successive censuses and the data is linked to other sources of ‘life events’ data such as birth and death registrations. The study is the principal source of whole population longevity statistics for England & Wales.