back to article DNA convictions fall as database doubles in size

The number of crimes solved thanks to the DNA database is actually falling despite the ever-growing number of people it contains. Figures given to Parliament show that even though 7 per cent of the UK population are now on the DNA database it helped solve only 0.36 per cent of crimes, down from 0.37 per cent last year. In the …


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  1. Psymon

    There's a suprise!

    Of course the number convictions that a DNA databse is going to help with is not going to increase.

    They don't need to revert to your double-helix when they have your licence plate!

    On the millenium eve, there was a total of 6 active officers on duty in Nottingham. That's because the rest were all parked on the outskirts, trying to catch that poor sod who'd had half an eggnog too much, and couldn't get a taxi for love or money.

  2. Mike Crawshaw

    No it doesn't.

    "The benefits of the NDNAD lie .... and in building public confidence that elusive offenders may be detected and brought to justice.”

    Not if the people I know are in any way representative of "the public". Even taking into account all the people I know whose wardrobe does not contain a tin-foil hat, I don't know a single person that thinks it's a good idea to have all these innocent people on the NDNAD "just in case". Not one.

  3. Peter Fielden-Weston


    The failure of the NDNAD to inprove crime detection & conviction rates, despite its increasing size shows that it has failed to provide the benefits given as its reason for being. In a commercial environment the NDNAD would not be scrapped and those employeed managing & maintaining it would be made redundant.

    Should this not happen it then becomes obvious that there are reasons for the existance of this database beyond that which the public have been told. I do believe that nobody resident in the UK today would be surprised at HM Goverment concealing its true objectives, or just plain lying to us.

  4. Hollerith

    my confidence is certainly increased!

    The Government keeps me so, so safe, and I certainly feel better knowing that almost a million children have their DNA registered.

  5. Jimmy Floyd


    It seems obvious to me that if you are not on the database by now then you are most likely to be guilty. Yes, it's all becoming clear now....

    Mine's the one with your DNA on it.

  6. Anonymous Coward
    Paris Hilton

    Seems biased statistics...

    So DNA only helps solve 0.36% of total crimes committed.

    But what percentage of crimes that are actually solved, were solved by DNA database? If the police only solve 1 in 4 crimes then its around about 1.5%

    And on the other hand, for how many of the 5 million crimes do the police actually bother to take DNA evidence? Given that the police now have a two day response time for buglaries I can't imagine many get referred. So the DNA database probably solves a high proportion of the crimes that are actually referred to it (and presumably it would be higher still if it had more samples).

    The cost: £1.6M which solves 17,600 crimes, making a cost of £90 per crime solved - how can that not be seem as good value given the likely overall cost of the traditional police investigation that might otherwise arise?

    It seems especially good value since it is probably only used for the nastiest sort of crimes (it is unlikely to be used for driving off without paying for petrol).

    Paris, 'cos she knows how to get a DNA sample.

  7. Anonymous Coward
    Anonymous Coward

    @Seems biased statistics...

    Your sums are a bit off: £1.6M AND YOUR PRESUMED INNOCENCE which solves 17,600 crimes, making a cost of £90 AND YOUR PRESUMED INNOCENCE per crime solved.

    Me, I'd rather be free than safe :-(

  8. Anonymous Coward
    Black Helicopters

    It contains internal evidence of its crapness

    "...4.7 million records on the English and Welsh database relating to some 4.1 million individuals..."

    If it was worth anything, it would be able to prevent duplicate records being committed to permanent record and would identify instances when an "alias" was given to the police. Or is there a 14% chance of a true match between 2 different individuals?

    Since they can't even maintain deduplication when they have "perfect" (one in a billion, is it?) unique identifiers, you have to conclude that the whoe thing is a crock.

  9. mike

    Percent on DNA DB by ethnic group

    I thought it might give some interesting results to combine the data in this article with the 2001 Census figures. So I had a play in excel over lunch and the differences were much larger than i was expecting, although not entirely surprising.

    Percent on DNA Database

    Those who say they are white: 6%

    Those who say they are Asian: 8%

    Those who say they are Black: 21%

    Those who say they are Chinese: 11%

  10. Anonymous Coward

    @seems biased statistics

    I hardly know where to begin my rant, there are so many points to argue with, are you a troll??

    "It seems especially good value since it is probably only used for the nastiest sort of crimes (it is unlikely to be used for driving off without paying for petrol)." gave me a good laugh though, haven't laughed so much for a long time!


  11. Britt Johnston

    consenting youth threat

    It would be possible to have 100% coverage, and still not solve any crimes. The reduced efficacy by increasing coverage suggests that there are other agendas.

    As nearly one quarter of the records are from persons aged 10 - 17, capturing young person's DNA records is likely to be one of these.

    I would have imagined it is used much less for minors, as voluntary consent - the basis for DNA testing - probably also should require parental approval. Can anyone who knows explain?

  12. Brian
    Thumb Down


    The fact that despite the ever increasing size of the database the number of crimes solved with the use of the data is static seems odd, until you bear in mind that the vast majority of new additions to the database are likely to be model citizens who happen to have been arrested for some reason, and aren't likely to be out committing crimes again.

    It's just diminishing returns - if the database was restricted to violent crime / robbery etc., we'd probably see the same clear-up rate.

    It's just keeping data on citizens for the sake of it - not unusual under Neues Arbeit.

  13. Anonymous Coward
    Anonymous Coward

    Value for Money

    Of course the ratio of crime detection rate against the total number of DNA profiles stored will reduce over time, anybody who knows anything about crime will tell you that most crime is committed by repeat offenders - as more people are added to the DB, most of those will be completely innocent.

    So the value of collecting more and more DNA samples from people will reduce. Yet, the expense of running the database will increase. Therefore, over time, the value for money will decrease.

    So, my question is, at what point, at what value for money threshold are they going to say "enough is enough, the value of the DB is deteriorating, we don't to collect more and more samples of innocent people".

    It's a fishing expedition, collecting samples from convicted and entirely innocent people just in case they're ever used. Pointless. Far better to collect DNA samples from convicted people only as they're most likely to re-offend, and the running costs of the DB will be cheaper.

  14. Ash

    @Seems biased statistics... (AC)

    What's this? A coherrant and well considered rebuttal? HM Gov could use people like you...

    Oh, wait... You too picked and chose your statistics. Further, you speculated and failed to citate. Guess you already work for them.

  15. Anonymous Coward
    Anonymous Coward

    Prior convictions at trial.

    Of course, if the trial evidence includes a match on the DNA DB then the accused must have been guilty of something in the past, therefore the jury is biased, and the convictions are unsafe.

    Best to avoid it.

  16. Graham Marsden

    not only in detecting the guilty but in eliminating the innocent

    Erm, excuse me? "Eliminating the innocent"?

    "Sir! We've found some DNA and compared it against the DNA of everyone in the country, so that's sixty million people we know *didn't* commit the crime!"

    "Excellent, that only leaves us with a dozen or so people whose DNA matches the sample, so let's hassle them all until someone coughs..."

  17. bogwoppit

    to be fair

    The database can only play a role in conviction for "repeat offenders" (used loosely since the DNA deposit isn't necessarily made following a conviction). That means there's likely to be a large time lag between deposit and "usefulness". Given that crime is skewed towards repeat offenders (who may have spent a few years in the can in between offences) this effect is exacerbated.

    So the more time that goes on, the more effective the database will get, and comparing the size of the database today to recent convictions is not a fair comparison.

    There's also the issue of deterrence - if you're on the database you know you're more likely to get caught so maybe you're less likely to offend. And that is impossible to quantify.

    Of course, none of this has anything to do with the ethical considerations (personally I believe the database should contain samples from either everybody or nobody).

  18. Anonymous Coward
    Anonymous Coward

    Re: Seems biased statistics...

    Ahh, looks like the above post has been magiced up up some government stooge. That, or one of the terminally braindead who vote for the facists like the Cracki Smiths of this world.

    Very nice attempt to spin the figures there. Well done, you have managed to make a .36% figure appear as 1.5%.... well, that's still fuck all and in absolute numbers its the same.

    You also assume that the crimes that the dbase helped solve were only solvable because of the database. This will not be the case at all.

    You then seem to proceed to prattle on about value for money. This database has cost 3.64 million to run over the last 2 years, god knows how much before then and probably a huge figure to set up initially. How much education could have been provided for this much money? Probably enough to have an effect on crime levels in the future, but putting money into schools isn't a vote winner, and doesn't pander to pillocks.

    And then you close your comment with an attempted appeal to emotion. Whenever I see an appeal to emotion I know that the other person doesn't have a valid argument, so their point of view is usually best dismissed.

  19. Martin Gregorie Silver badge

    FP avalanche?

    "The number of crimes solved thanks to the DNA database is actually falling despite the ever-growing number of people it contains."

    Maybe there's a correlation. The number of FPs will grow with the size of the database, so maybe the number of FPs has now reached the point where the effort of tracking down and eliminating falsely fingered felons overwhelms the benefits of using it.

  20. Mycho Silver badge


    She doesn't take proper measures to prevent the sample being contaminated by other samples from what I heard.

  21. Anonymous Coward

    that sentence is too long

    The benefits of the NDNAD lie not only in detecting the guilty but in eliminating the innocent from inquiries, focusing the direction of inquiries resulting in savings in police time and in building public confidence that elusive offenders may be detected and brought to justice.

    Should clearly have read: The benefits of the NDNAD lie.

  22. Anonymous Coward
    Anonymous Coward

    1million children on it?

    WTF are 1 million kids doing on it? You're treating 1 million kids as criminals, you're lowering the threshold for them to commit further crimes and setting them off on a life of crime with a tainted record? Why?

    To prevent crime you need a large gap between how you're treated as an innocent person and how you're treated as a criminal. By treating people as criminals you're reducing that gap. What do they have to lose?

    What a hate filled Home Secretary!

    And what does that 1.4 million "all other recorded crime" figure contain? Does it include ASBOs does it include all the NuLabour pretend crimes? Does it include cautions etc.?

    I don't consider cautions as admissions of guilt despite the claim that a caution requires guilt be admitted.

    If they were, then there would be no cases where an officer TRIES for a caution but fails, then fails to pursue the prosecution. It follows for that to happen, the officer must believe they can get a caution accepted where he couldn't get a conviction. So the threshold for a caution must be LOWER than that for a conviction and you can't treat a caution as like for like guilt as though it had gone to court and been prosecuted.

    See the case of the Wifi 'theft' the other week, where an officer tried for a caution by a kid had connected to next doors Wifi, but when that was refused he failed to pursue a conviction. He can't have it both ways, either

    Also, can a child be given a caution? I read there that the PARENT rejected the caution, but then if the parent ACCEPTED the caution, it's the parent admitting guilt on behalf of the child. How is that possible. How can a person accept guilt for someone else???

    We don't accept children can make the decisions as adults, which is why we don't let them make lots of decisions, including the right to vote. Yet someone else can give them a criminal record?

    To me, the way crime is handled in the UK with children is just a function of a hateful old bitter bitch who sits in the Home Office with zero tolerance for others.

    She's the problem here, her and her hate filled mind.

  23. Jonathan Hogg
    Black Helicopters

    "eliminating the innocent from inquiries"

    Ah, so having all those people on the database isn't to allow massive trawling operations for the guilty, it's to protect the innocent. Thank god. I'm a supporter now.

  24. RW

    Just another demonstration

    That an über-plod has the ear of the Home Secretary. After my last inquiry here about the history of the Home Office's love of Stasi methods, I ran across the name of the particular cop who has access to The Ear.

    Here's the root problem: Wacqui Jacqui and her predecessors don't understand that they're not in office to help the police on the q.t. The police are quite capable of helping themselves. WJ et cie are there to rein in the police and make sure that in their plodish way freedom is not tossed into the trashcan.

    Better that a thousand criminals go unpunished than one innocent person suffer.

  25. David Pollard

    Crime scene profiles vs NDNAD

    The crucial information required to assess the usefulness of the NDNAD is the proportion of detections that can be made from the crime scene profile database.

    Aside from a small and diminishing number of cold crimes, the NDNAD of personal profiles - including those of convicted persons - could probably be scrapped without significantly reducing detection through DNA alone were the resources to go instead into increased profiling of crime scenes.

    The increase in public co-operation from scrapping the Orwellian aspect would most likely more than compensate for any shortcoming. Public co-operation, when it's there, is the police's most useful asset.

    But figures aren't available to compare the effectiveness of the crime scene database with that of the NDNAD.

    Yours are the ones with my DNA on it. (Think about it.)

  26. Anonymous Coward
    Anonymous Coward


    "combine the data in this article with the 2001 Census figures" - got the postcodes as well, perchance? MySociety could do a mashup.

  27. David Mery
    Black Helicopters

    Data for 10-17 does not fully compute

    From the Parliamentary answer linked in this article there are as of 16 July 2008, 1,057,961 DNA profiles of individuals aged 10-17 (at the time of the report) that were added by the England & Wales forces (estimated to be for 917,252 individuals).

    From the data obtained via FOIA and analysed in, as of 10 April 2008 there were 349,934 DNA profile of individuals aged 10-17 (at the time of the report) that were added by England and Wales forces, and of 1 September 2008 that number was down to 343,745.

    So the numbers are:

    2008-04-10: 349,934

    2008-07-16: 1,057,961

    2008-09-01: 344,745

    Some changes are to be expected due to people getting older but the effect tends to be to reduce this statistics. In a further comment by email from the NPIA when I queried the small discrepancy between the April and September figures, I received the following explanation: "The reason the figures have decreased is because peoples ages are continually changing i.e. some of the people counted in the original count of 10/04/08 are now aged over 17 so would no longer be counted in the report when it was ran on 1/09/08."

    Apart from a missing decimal point in one of the cell in the table in the Parliamentary answer, the numbers seem to add up. It is difficult to grasp how this stat could jump up by 708,027 in a few months to then reduce by 714,216 in the second half of July and August. 700,000 is close to the number of DNA profiles added yearly, for all ages so it seems unlikely that the Police arrested just before July hundreds of thousands of individuals who had their 18th birthday in August.

    br -d

  28. Michael Palmer

    DNA Database: A Public Relations Tool?

    At a few million quid not a too expensive one (in terms of government expenditure). Personally I think the database would work better if only the DNA of convicted criminals was taken, since they're the ones who commit the majority of the crimes.

  29. Anonymous Coward


    "I would have imagined it is used much less for minors, as voluntary consent - the basis for DNA testing - probably also should require parental approval. Can anyone who knows explain?"

    If the child is over 10 and is arrested by the police and subsequently cautioned DNA WILL be taken with or without consent of the child or parents. Their details stay on the db until they are 18 in theory although the nice policeman said it effectively means it will be kept for 100 years.

    That is what New Labour has brought us. Donl't you feel proud?

    Not sure what happens to the under 10s.

  30. Anonymous Coward

    @1 million children on it?

    I have a 12 year old boy who was cautioned and his DNA taken just for throwing a stick at a girl. When I expressed my concern to his solicitor, he just said "Get used to it with in a few years all our DNA will be on the database". Is it a coincidence that NDNAD looks and sounds similar to NSDAP?

    Mines the one with the airline tickets to Iran, where it's less oppressive.

    Heil Braun!

  31. Geoff

    I sumpport the database

    The figures show that the database cost £90 per crime case that it helped with. That is small change and a very significant benefit in terms of police resources.

    The part I really like is that criminals can now be caught when they are NOT on the database. If his parents, siblings or children are on the database the near match can greatly assist the police in their enquiries.

    I am law abiding and have no fear from the database.

  32. Anonymous Coward
    Anonymous Coward


    "The benefits of the NDNAD lie .... and in building public confidence that elusive offenders may be detected and brought to justice.”

    In plain English:

    "Resistance to the NuLab machinery of compliance and oppression is futile. Fuck off".

  33. Anonymous Coward
    Anonymous Coward

    @Percent on DNA DB by ethnic group

    Where are you getting your numbers from ?, what were you doing on excel playing with the rand function ?

    According to the article, ethnicity ( based on appearance ) was:

    Records on DB

    White : 3,294,760 = 85.0%

    Asian : 226,938 = 5.8%

    Black : 325,422 = 8.4%

    Chinese etc : 26,300 = 0.67%

    Total : 3,873,420

    According to the ONS (

    Ethnicity (based on self selection )

    White : 92.1%

    Mixed : 1.2%

    Asian : 4.0%

    Black : 2.0%

    Chinese : 0.4%

    Others : 0.4%

  34. Mark

    re: "eliminating the innocent from inquiries"

    Worse, there's no need to keep your DNA if you're innocent. If you are a suspect they can take your DNA there and then and check it against the DNA of the person that did the crime. There's no need to keep a record because you still have all your DNA available.

  35. Mark

    re: It contains internal evidence of its crapness

    "...4.7 million records on the English and Welsh database relating to some 4.1 million individuals..."

    Ah, maybe because some people are chimeric. They have more than one entities DNA in their body.

    14% would be high, but maybe someone has, like 250,000 different human DNA strands in their body.

    Naughty mommy...

  36. Mark

    re: I sumpport the database

    That's £90 of continuing operation cost, not the cost of the system amortized and the opportunity cost (or NPV equivalent) of this initial rollout cost.

    And if the DNA had not been needed in the case, that is £90 that didn't have to be spent.

    Now, if all these laws, all the expense is justified in the War On Terror because of these terrists' hate of our way of life (in that it isn't their way of life), then our way of life has value.

    Is it more than £90 per person per year?

    Well, taking just the money directly spend on merely Iraq and Afghanistan ALONE were taken into account, YES would be the answer.

    So therefore, this is a net reduction in the value of the average UK resident.

    Therefore, if cost is your only consideration, you must reverse your support.

    Of course, if that was merely a justification for your wishes, your support will not change. In that case, kindly stop saying that the cost makes it worth it. Because the cost is not your reason for support.

  37. peter

    When they take my DNA......

    How do I answer the question of my ethnicity?

    I am mostly English ( British?), part African, part Chinese and part Irish (we think - family history is a bit vague on that point). I was born in Africa, mostly raised in Hong Kong, lived in the Med and finished my schooling in the UK. I look middle aged white.

    I describe myself as White African whenever I get asked. Does my heart good to see the confused looks on peoples faces when I say that.

    I also have a friend who was born and raised in the West End. He describes himself as White British just to see if anyone tells him he is being silly. Not a single person has has had the non-politically correct balls to contradict him with the fact that he is as black as coal. When they ask after his parents, he tells them truthfully they are a both British White (he is adopted)

    The silly games people play. Tee Hee

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