The BBC mentioned a study yesterday that refuted the 600,000 figure on the
grounds that "houses near main roads were over-represented" (my paraphrase).
From the Lancet article it does appear that households on SHORT street near
main roads will have been over-represented. (However, households on main
roads appear not to have been sampled at all.
If "distance from main road" was collected, as it easily could have been, it
would be possible to attempt some control for this factor.
Has anybody been in touch with the Johns Hopkins people about our
discussion? (I bet they are fed up with it by now!)
========
I was concerned by Triesman's explanation of why the UK government does not
interest itself with the accuracy of such figures. (see Ted Harding's
earlier email.)
JOHN BIBBY
========== From NZ!: http://www.scoop.co.nz/stories/WO0610/S00436.htm
Lancet Iraq Study Flawed: Death Toll Too High
Friday, 20 October 2006, 10:36 am
Press Release:
Lancet Study Fundamentally Flawed: Death Toll Too High
October 19, 2006 – 1 page –
For immediate release:
Researchers at Oxford University and Royal Holloway, University of London
have found serious flaws in the survey of Iraqi deaths published last week
in the Lancet.
Sean Gourley and Professor Neil Johnson of the physics department at Oxford
University and Professor Michael Spagat of the economics department of Royal
Holloway, University of London contend that the study’s methodology is
fundamentally flawed and will result in an over-estimation of the death toll
in Iraq.
-> The study suffers from "main street bias" by only surveying houses that
are located on cross streets next to main roads or on the main road itself.
However many Iraqi households do not satisfy this strict criterion and had
no chance of being surveyed.
-> Main street bias inflates casualty estimates since conflict events such
as car bombs, drive-by shootings artillery strikes on insurgent positions,
and market place explosions gravitate toward the same neighborhood types
that the researchers surveyed.
-> This obvious selection bias would not matter if you were conducting a
simple survey on immunisation rates for which the methodology was designed.
-> In short, the closer you are to a main road, the more likely you are to
die in violent activity. So if researchers only count people living close to
a main road then it comes as no surprise they will over count the dead.
During email discussions between the Oxford-Royal Holloway team and the
Johns Hopkins team conducted through a reporter for Science, for an article
to be published October 20, it became clear that the authors of the study
had not implemented a clear, well-defined and justifiable methodology. The
Oxford-Royal Holloway team therefore believes that the scientific community
should now re-analyze this study in depth.
The team can be reached for comment at;
Gourley: s.gourley1 @ physics.ox.ac.uk mobile:+44 (0) 7733113558
Johnson: n.johnson @ physics.ox.ac.uk
Spagat: M.Spagat @ rhul.ac.uk
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.408 / Virus Database: 268.13.5/483 - Release Date: 18/10/2006
******************************************************
Please note that if you press the 'Reply' button your
message will go only to the sender of this message.
If you want to reply to the whole list, use your mailer's
'Reply-to-All' button to send your message automatically
to [log in to unmask]
Disclaimer: The messages sent to this list are the views of the sender and cannot be assumed to be representative of the range of views held by subscribers to the Radical Statistics Group. To find out more about Radical Statistics and its aims and activities and read current and past issues of our newsletter you are invited to visit our web site www.radstats.org.uk.
*******************************************************
|