Top 10 evidence gaps in information about UK immigration

A new report by Oxford University researchers reveals ten key problems with the UK’s evidence base on migrants and migration. The report is by the Migration Observatory, a project of the University’s Centre on Migration, Policy and Society (COMPAS).

The Migration Observatory was launched by Immigration Minister Damian Green, MP and Baroness Oona King of Bow last week. The new multi-media platform aims to provide clear, authoritative and independent analysis of data on migrants and migration issues in the UK, set in an international context.

Dr Martin Ruhs, Director of the Migration Observatory, said: ‘There are many disagreements about migration in the UK, but one thing that unites everyone is that for many years there have been serious problems with the evidence base. Reform of immigration policy is currently a major government priority, which clearly requires solid evidence on which to base changes to the system.’

The report ‘Top Ten Problems in the Evidence Base for Public Debate and Policy-Making on Immigration in the UK’ has implications for public debate and policy making. According to the researchers, the ten key areas are:

Emigration : The limited data about who is leaving the country mean that net migration figures – which are based on the balance between those leaving and those entering the UK – are very imprecise.

Immigration : There are substantial discrepancies between the three data sources that provide information about people entering the UK - the International Passenger Survey (IPS), visa data and passenger entry data.

Net-migration : Two major data sources (the IPS and the Annual Population Survey) disagree significantly about the level and changes of net-migration over time.

The immigration status of migrants in the UK : While we know the purpose for which people have been granted access to the UK – work, family reunion, political asylum, etc – there is no systematic evidence about the number, characteristics and impacts of migrants on different types of residence permits in the UK

Local area statistics on migrants : The most reliable tool we have to measure the number of migrants at the local level is the Census, which is only undertaken every ten years. In intercensal years, survey data provide very imprecise estimates of migrants in local areas, making it extremely difficult for local government or services to estimate the resources they need accurately.

Public opinion : Public opinion data clearly show that the majority of the British resident population would prefer reduced immigration. But the evidence base lacks detailed information on a crucial issue – how do members of the public define “immigrants?”

Migrants’ impacts on public services : There is very limited systematic data and analysis about migrants’ use of public services, especially health and education, and even less information about migrants’ contributions to the provision of public services.

Impacts on housing : We know little about how immigration impacts, directly and indirectly, on house prices, rents, and social housing at national and local levels.

Student migration : The evidence base lacks sufficient information about the number of students, the extent of non-compliance with immigration rules among international students, and the impact of foreign students on the broader economy and society.

Irregular migrants (also referred to as undocumented or illegal migrants): Data and information about the number, characteristics and impacts of irregular migrants are extremely limited.

Dr Ruhs said: ‘No country can realistically expect to have perfect information about migration – collecting data can be complex and expensive – but if we want to have informed debate and effective policy-making, we need to make sure that we have the best possible evidence.’

Vice-Chancellor of the University of Oxford, Professor Andrew Hamilton, said: ‘This is an excellent example of where academic research can have a vitally important role and real impact in a debate of immense national and international significance.’

The Observatory says it has no political agenda, and draws on expertise from across a number of disciplines at Oxford University, with contributions from specialists in economics, law, criminology, demography, sociology, political science and many other subjects.

Its website offers briefings or analysis on key subjects; policy primers or in depth analysis; responses to current events and major policy decisions related to migration issues); and data and resources including charts, tables, maps and data on migration.