Introduction

The Northern Ireland Longitudinal Study (NILS) is a large-scale data linkage study which has been created by linking administrative and statistical data.  The Study is designed for statistical and research uses only and is managed under Census legislation. Information is linked over time on people from Census, vital events and health registration datasets.  Data sources include 2001 Census data, birth and death registrations and demographic data derived from health registrations.

A Longitudinal Study has been successfully running in England and Wales since the 1971 Census. The England and Wales Longitudinal Study (LS) was designed as a sample around 500,000 people from the England and Wales population.  A similar study, the SLS, is also running in Scotland with a sample of nearly 300,000 people from the Scottish population.

NILS members are selected on 104 annual birth dates. In total around 500,000 people are included in the Northern Ireland Longitudinal Study. The NILS dataset thus does not include 100% of the population but is rather a very large sample (approximately 28%) of the population.The study continues to be of great interest to a wide variety of researchers.  Accessto the NILS is governed by strict protocols and procedures to ensure data confidentiality and can only be used for statistical and research purposes. Information on using the NILS is provided in this website.

Introduction

The Northern Ireland Mortality Study (NIMS) is a large-scale data linkage study developed in 2006 that links mortality data from the General Register Office (GRO) to 2001 Census returns. While the 28 % NILS sample is satisfactory for the majority of analysis that researchers wish to perform, some projects, focussing on mortality, could not be permitted as the population being studied only contained a very small number of people. This is particularly true when investigating those dying of less common causes (e.g. accidental death). However there is considerable value to be gained in analysing mortality data using the added value from the Census. Thus a companion dataset to the full NILS has been developed in which 100% of the population as recorded in the 2001 Census is included. There are no other vital events data included in the NIMS dataset. However, the potential to examine a broader range of social, economic and geographical factors and their relationship with mortality rates remains. As with the NILS dataset, these anonymised data are held in a safe setting by the Northern Ireland Statistics and Research Agency (NISRA). The NIMS dataset is recommended to researchers who are studing mortality in Northern Ireland only.  Like the NILS dataset, the the NIMS is designed and maintained for statistical and research uses only and is managed under various legisalation including Census legislation.