A new report has highlighted ten major problems with the available evidence on the UK's immigration situation.
Compiled by the Migration Observatory at the University of Oxford, the study claims that its findings will have "profound implications for public debate and policy monitoring".
The report comes as the coalition government's efforts to reform UK immigration are being implemented.
Substantial reductions in the number of work permits and UK visas for students come into effect over the coming months.
However, the Oxford study has highlighted important gaps in the data used to inform these changes.
Dr Martin Ruhs, director of the Migration Observatory, commented: "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."
Limited data regarding people emigrating the country was one of the key problematic areas flagged up in the report.
This lack of information means that the net migration figures available to the government are "very imprecise".
UK immigration figures, meanwhile, were also noted as an issue, with "substantial discrepancies" recorded between the three data sources that provide information on people entering Britain.
Even public opinion of people already resident in the country cannot be relied upon, according to the report, since there is no clear definition of the work 'immigrants' when people are questioned on their opinions.
Dr Ruhs conceded that no country can realistically expect to have "perfect information" on the topic, but informed debate and effective policy-making require "the best possible evidence".