Select Committee on Science and Technology Written Evidence


Memorandum from Dr John Daugman, University of Cambridge



  Public discussion of scientific issues related to biometrically-enabled ID cards has been of poor standard. This is because public debate about the proposed biometric ID cards has been dominated by a single document, the "LSE Report," which had no natural scientists amongst its putative or actual authors. Persistent errors of fact are repeated both in that Report and in the parallel press campaigns run by its organisers. This Memorandum documents some of the misinformation and recommends that in future the broad scientific basis for policy proposals should be assembled in an on-line web resource containing balanced and critical empirical documents. This may prevent future hijacking of public discussion by scientifically misinformed assessments that are spearheaded by activists under academic cover.

  1.  I thank the Science and Technology Committee for inviting my comments about the way in which the Government obtains and uses scientific advice, specifically in connection with the proposals about identity cards. The aspect on which I wish to comment is the way in which the public debate, and to a significant extent the Parliamentary debate, on this issue has been influenced by scientific misinformation from lobbyists opposed to the proposals. In some cases (which I will document here) it could even be called disinformation. Of relevance under the Terms of Reference of the present Inquiry is whether such tactics have influenced policy formation or assessment, and whether in its public communications the Government has adequately challenged the scientific misinformation.

  2.  Immediately prior to every Reading of the ID cards bill in either House, a report ostensibly prepared by senior academics at the London School of Economics was widely disseminated. The putative LSE authors included no scientists. Moreover the LSE Reports were spearheaded and apparently written not by the LSE Professors whose names appear on them, but by Simon Davies, who is Director of Privacy International, a political lobbying organisation fiercely opposed to the concept of citizen identification.

  3.  Although recent debate has shifted mainly to questions of cost, a major focus earlier was the scientific and technical feasibility of biometric identification of persons across a national database. Both the LSE Report and a wider press campaign by the same source to influential media (including The Economist; New Scientist; and the broadsheets) asserted repeatedly that biometric identification simply would not and could not work. Arbitrary statistics about False Match rates were fabricated from thin air and presented as scientific facts in that media campaign, contradicting all available scientific evidence, as I shall detail more fully in paragraph 9.

  4.  However ambiguous or contrived may be the authorship of the LSE Report, the absence of any natural scientists from amongst even its putative authors may explain the persistent errors of scientific fact that appear within it. Many of these arise from confusing the iris with the retina. (The iris lies near the front of the eye, in front of the lens. The retina lies at the very back of the eye.) These simple errors when assessing the feasibility of the iris biometric, for example if the lens of the eye becomes cloudy from cataract, occur equivalently both in the "Interim" release of the LSE Report dated 23 March 2005 and in its final release dated 27 June 2005, and so henceforth I shall refer to both releases collectively as "the LSE Report."

  5.  Glaucoma, diabetes, cataracts, blindness, and pregnancy were all incorrectly said to affect the iris pattern, or its visibility: "People with glaucoma or cataracts may not be reliably identified by iris recognition systems." "People with diabetes . . . will not be able to use this biometric method." In fact glaucoma affects the retina, not the iris. Cataract clouds the lens, which lies behind the iris and which therefore does not affect the visibility of the iris. Diabetes may affect the retina, not the iris.

  6.  It is informative to trace the origins and promulgation of so many basic misunderstandings. Invariably in the biometrics debate the sequence is that statements which began as speculation or simple errors in earlier reports or in the press, become cited as established facts in later documents without further investigation. This is the ubiquitous standard of scientific evidence in the LSE Report. For example it is taken for granted that blind persons, or those with visual disabilities, must lack eyes or lack visible irises. (The blind former Home Secretary David Blunkett successfully used an iris recognition system.) When I pursued one such confusion about eyes with the authors of a document submitted to the Commons Home Affairs Committee by the British Computer Society, I learned that they further believed that the iris "shatters at birth."

  7.  Most bizarrely, the LSE Report asserts that "Pregnancy . . . can affect the recognition of irises;" and that "Patterns in the eye may change over time because of illness," and that "using the iris image for health diagnostics" is a concern. This practice, and these beliefs, are called Iridology. All published scientific tests of Iridology (see bibliography at have dismissed it as medical fraud. Yet this belief in systemic changes in iris patterns seems to be part of the basis for the LSE high cost estimate for the ID cards scheme, as the Report asserts that the biometrics would need to be re-enrolled frequently for these reasons.

  8.  Besides scientific inaccuracies such as those cited above, the influential LSE Report was extremely selective in the data that it cited. It ignored completely the very positive test data about large-scale biometric capabilities reported for example by the US National Institute for Standards and Technologies. In particular, it ignored eight published studies conducted over the past decade about the accuracy of iris recognition, each one finding no False Matches. Two of those reports were particularly germane to the contemplated large-scale UK deployment, as they showed that with reasonable thresholds it was possible to perform two billion iris cross-comparisons without making any False Matches (IBG ITIRT Report 2005); and indeed 200 billion iris cross-comparisons were performed without encountering any False Matches (University of Cambridge Technical Report UCAM-CL-TR-635, 2005). The origin of such resilient performance is the mathematical principle of binomial combinatorics embedded into the iris recognition algorithms, a topic which again has eluded any public discussion. The scale of this huge number of iris cross-comparisons (200 billion) without making False Matches is not widely appreciated. It is larger than the estimated number of stars in our galaxy; it is larger than the estimated number of galaxies in the universe; and it is larger than the estimated number of neurones in the human brain.

  9.  Yet in earlier phases of the campaign against ID cards, several influential journals (including The Economist and New Scientist) and press were told by the organiser and author of the LSE Report that iris recognition has a "False Match Rate of 1%;" that "for every 100 scans, there will be at least one False Match," and that therefore in a nation of 60 million persons, "each person's scan will match 600,000 other records in the database." (Simon Davies, New Scientist 180, no 2422, page 13.) This statistic was simply conjured out of thin air with no basis in fact, and obviously it contradicted dramatically all of the above-mentioned studies. Nonetheless it was published as a fact without further investigation.

  10.  Every day today some seven billion iris comparisons are performed in a national security deployment covering all 27 air, land, and sea ports of entry into the United Arab Emirates, comparing arriving passengers against a central database of iris patterns. (About 9,000 daily arrivals are each compared by real-time exhaustive search against an enrolled database of 800,000 IrisCodes, making 7.2 billion iris comparisons per day.) According to the UAE Ministry of Interior, over the past 4.5 years this system has caught some 50,000 persons trying to enter or re-enter the UAE under false travel documents. If the putative 1% False Match rate were correct, then the daily volume of seven billion iris comparisons would be producing 70 million False Matches per day. If this were true, I should have thought someone would have noticed.

  11.  Both the LSE Report, and the parallel media campaigns arguing that biometric identification cannot work, have been highly influential. The Leader of the Opposition, David Cameron, stated on 15 January 2006 (BBC, Andrew Marr's Sunday AM Programme) that he based his objection to the ID Card proposals primarily on the LSE Report's conclusion that the system would be unworkable. Commons MP and Home Affairs Select Committee member the Rt Hon Bob Russell (Lib Dem) declared that iris cameras would cause epileptic fits, and that trained medics would need to be standing by at each one. New Scientist (180, no 2422, page 13) asserted that the iris is a kind of thermometer, changing its pattern with temperature. The conclusion of the LSE Report about the technical feasibility of biometrics (page 184) was that "Implementing biometrics [in the UK] could bring the country to a standstill."

  12.  Conclusion: The science of biometric pattern recognition and its underlying mathematics has been not only ignored but contradicted and overwritten by political campaigners against the Government's ID cards proposals. In effect this important part of the discussion has been hijacked, as have also been some academics. Under these unusual circumstances, with public debate so steered by a scientifically misinformed document and a parallel press campaign, the public interest may have been better served by a more robust presentation from Government of the scientific basis and technical capabilities of biometrics. One mechanism whereby this might be achieved in future would be to create and maintain an on-line website resource containing a balanced and critical collection of scientific papers and reports that inform and address public policy proposals.

January 2006

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