The DNA database and you

How big is it? How many get off it? Your questions answered...

Define innocent

A common question is how many of these individuals are innocents. This is particularly difficult to find out.

First, the National DNA Database was allegedly never set up to record this information; this is in the Police National Computer (PNC).

Second, what is meant by innocent is not always consistent; the obvious definition of all those never charged and those acquitted may not map directly to the information available. The NPIA ran a report on 2008-03-31:

(At 2008-03-31 for England & Wales forces)	Total individuals	Percentage of total
With a conviction, caution, formal warning or reprimand	3,259,347	79%
No conviction, caution, formal warning or reprimand listed	573,639	14%
Not known as PNC record removed	283,727	7%
Estimated total number of individuals	4,116,713	100%

From the above table it can be deduced that, as of March 2008, there were DNA profiles for at least 573,639 innocent individuals and possibly for as many as 857,366 innocents. Fourteen to 21 per cent of the sampled individuals recorded in the NDNAD are innocent. Furthermore, that does not take into account any mistakes in the PNC.

What happens to the DNA samples and profiles of all those innocents? Most of them are kept and retained forever. The procedure to get off the NDNAD is complex and assume that one case is considered exceptional enough to justify such a procedure in the first place.

See El Reg's How to delete your DNA profile for more on this. (Note that the only process map the Metropolitan Police has published since is a rehash of the usual guidelines and the Specialist Crime Directorate 12 wrote that '[t]here is no additional information I can supply on this subject'.)

Subject profiles removals	2003	2004	2005	2006	2007	2008 (adjusted)
England & Wales forces	677	34	81	271	310	222
Other forces	23,492	19,160	21,580	21,969	21,265	19,164

The huge difference in numbers between removals of samples taken England & Wales forces and by other forces is due to differences between English & Welsh and Scottish laws. DNA profiles and samples of innocents taken by Scotland forces can't be kept forever.

Whether England and Wales forces can keep stalling on the removal of DNA profiles (and destruction of DNA samples) of innocents has gone all the way to the Grand Chamber of the European Court of Human Rights:

"The [Marper and S v. UK] case concerns the decision to continue storing fingerprints and DNA samples taken from the applicants after unsuccessful criminal proceedings against them were closed." The hearing was in February and the ruling will be given later this year. (Note that the adjusted figure for 2008 is based on data up to September adjusted for the rest of the year.)

I did not request the data for calendar additions to the NDNAD, but to put things in perspective, the yearly average number of subject profiles added to the NDNAD for the the financial years 2005-07 was 711,645 (NPIA NDNAD Annual report data). For England and Wales forces it was 646,767 (John Reid in Parliament written answers).

Profiling at a young age

There's particular concern as to how many young individuals are included in the NDNAD. Depending on whether you consider the NDNAD as a criminal database, being included in it at a young age is worrying.

(At 2008-09-01)	England & Wales forces	Other forces
Total subject profiles from 10-17 year old	343,745	10,671

The England & Wales forces again lead in in their aggressiveness to sample DNA. Six pe rcent of all the profiles in the NDNAD were taken by other forces, but only three percent of the DNA profiles of subjects 10 to 17 years old (when the report was ran) was for samples taken by other forces.

The NPIA last ran a more complete report concerning 10-17 year-olds on 2008-04-10:

(At 2008-04-10 for England & Wales forces)	Total individuals	Percentage of total
With a conviction, caution, formal warning or reprimand	264,297	87%
No conviction, caution, formal warning or reprimand listed	39,095	13%
Estimated total number of individuals	303,393	100%

(The number of those with a PNC record is one less that the estimated total number of individuals. The NPIA did not state if there's one youngster with a PNC record already removed, which is unlikely or whether this should be viewed as a statistical error). From the above table, it can be seen that at least 39,095 innocent youngsters are affected.

If you happen to live in England or Wales, being young or innocent, or both, is not enough to ensure you won't be captured in this massive database. ®

Bootnote

It can be argued that retaining DNA profiles of individuals is not even effective in solving crimes. Helen Wallace, from GeneWatch, debunked this assumption last year when looking at who should be on the NDNAD:

"Collecting more DNA from crime scenes has made a big difference to the number of crimes solved, but keeping DNA from more and more people who have been arrested - many of whom are innocent - has not. Since April 2003, about 1.5 million extra people have been added to the Database, but the chances of detecting a crime using DNA has remained constant, at about 0.36%."

David Mery is a technologist and writer based in London. Last year he succeeded in having his DNA profile purged. His website is gizmonaut.net.