Letters: Taylorism?
The complaint about interviews, psychometric testing and other personnel
selection methods (Forum, 18 June) is that, as tests, they produce a noticeable
proportion of false positives.
However, in the absence of anything better, such procedures can only
be rejected if they also produce a large proportion of false negatives –
if the majority of rejections are sound, use of the method has served a
useful purpose. The problem is that the rate of false negatives cannot be
determined since, by definition, the assumption that rejected candidates
would have proved unsatisfactory in-post is not put to the test.
The currently fashionable denigration of the interview as a selection
tool is based on the false premise that the suitability of individuals for
a particular task is solely a matter of assessing some objective competence
which we could measure if only we knew how.
This overlooks the obvious but politically inconvenient fact that work
is first and foremost a social activity and personal relationships matter.
Reversion to a crude form of Taylorism is simply to duck the issue.
How does Adrian Furnham select his staff?
David Neil Macclesfield
Letters: Taylorism?
The issue is indeed the link between the test and performance. The ‘un-asked’
question is, ‘What drives performance in the first place?’ The answer, sadly
for the ‘test junkies’, is that organisational conditions have a far greater
influence and account for the bulk of the variance in performance. Our own
research has shown that things like clarity of purpose, knowledge of contribution,
management thinking and behaviour, inter-group support and freedom to act
have far more impact on behaviour than individual differences.
Richard Davis Vanguard Ltd, Hereford
Letters: Remember the land
It is obvious that everything possible should be done to prevent the
pandemics of rinderpest that have been a scourge throughout Africa over
the past 100 years (‘Man with a mission’, 18 June). We are, however, appalled
by the comments of the writer Mary Anne Fitzgerald that, following eradication
of the disease, herds could be enlarged, the door could be opened to European
breeds, and the export of beef to nearby Arab States would bring in millions
of dollars of foreign currency.
First, an increase in the numbers of cattle would further destroy the
fragile grazing lands of the Sahel.
Secondly, we find it extraordinary that the Eurocentric view still prevails
that European cattle would be an improvement over the indigenous breeds,
such as the Borano, which have become fully adapted to their arid environment
over thousands of years.
Thirdly, attempts to earn foreign currency through ranching cattle on
land that is already at the limit of its productivity can only lead to increased
poverty for the human population. Rich countries might enjoy more beef,
but Africans would suffer further degradation of their land.
Tilahun Yilma’s remarkable achievements in biological research could
be the beginning of a revolution in animal production in Africa but they
will turn achievement into disaster unless the daunting ecological problems
are tackled at the same time. Building on the age-old adaptations of local
breeds of cattle, improving them and their management, led by African experience,
is the best way forward for the pastoral economies of Ethiopia, Sudan, and
Somalia.
Juliet Clutton-Brock Natural History Museum Peter Jewell University
of Cambridge
Letters: Forest facts
From the article ‘Damage to Britain’s trees is not so natural after
all’ (This Week, 18 June) it would seem that Fred Pearce had some difficulty
in interpreting results presented in our report on Forest Condition in Great
Britain 1989 to 1992.
Although there were significant relationships for changes in dieback
in beech with ozone, crown density in Norway spruce with sulphur deposition
and flowering in Scots pine with ozone, the models explained only between
5 and 10 per cent of the total variation in crown condition. The variation
explained by modelled pollution alone was considerably smaller.
Additionally, it has not so far been possible to account for the likely
effects of mechanical damage (that due to wind, snow and storms) on forest
condition. This is a major limitation to models, in that it is highly probable
that some of the variation attributed to sulphur deposition (which tends
to be greatest in elevated and exposed areas) may in fact be due to mechanical
damage.
Other limitations are that analyses were based entirely on modelled
meteorological and pollution data. Although representing the best available
data, models provide only an approximation to the environmental conditions
experienced at specific locations. There were also other additional important
factors (particularly damage by insect pests) for which we do not have information.
Any comment on statistical results of this report without addressing the
limitations of the data and methods of analysis would be a misrepresentation
of the facts.
If Fred Pearce had consulted earlier publications by the Forestry Commission,
he would have found that the results are entirely consistent with earlier
work reported by the Forestry Authority. The overall indication is that
although pollution may be a factor in influencing the health of British
trees, its role is probably small. In fact, the analysis described in our
report does not establish any causal link between pollution and the forest
condition.
The main value of this work is that it suggests approaches for separating
and identifying effects due to different environmental (and pollution) influences.
Richard Mather and Peter Savill University of Oxford
Letters: People can decide
Susan Katz Miller’s article, ‘Genetic first upsets food lobby’ (This
Week, 28 May) was a good article for the activists, but it did not provide
a very balanced picture of the situation. It did not explain that biotechnology
is only a set of tools that allows scientists to be more precise in their
breeding programmes. Or that this precision will allow scientists to produce
healthier, safer, and more nutritious foods to meet the needs of a fast
growing population.
It said ‘many Americans have been hostile’ to the genetically engineered
hormone BST, but it overlooked the fact that milk consumption in the US
has not dropped since BST was introduced. Who are the ‘many’ that are boycotting
milk?
I understand that the Flavr Savr Tomato is being bought as quickly as
it enters the stores. Who is behind this acceptance of the products of biotechnology?
Is it the 280 million plus Americans who are not part of Jeremy Rifkin’s
27 000 activists?
As with any new product, there are those that want it and those who
do not; however, the public does have an uncanny capability to decide for
itself. Therefore, with a solid scientific base and an excellent regulatory
process to make decisions based on solid sciences, products of biotechnology
should be allowed to enter the marketplace.
Murray McLaughlin Ag-West Biotech Saskatoon, Canada
Letters: Dissimulation
It is pleasing to see you devoting space to perceptual theory, but the
interpretation you place on a recent study (This Week, 18 June) is in itself
dangerous. The study by Doug Stewart et al., of ‘driver misjudgments’ was
a useful research contribution, but you failed to mention that the ‘computer
simulation’ was merely of white bars moving on a black computer screen.
In this context, many of the critical depth cues are absent. Linear
perspective, texture gradients and the driver’s head motion all provide
very salient information about relative depth and size, and stereo-vision
has been proposed as a means of absolute depth scaling.
All these features are present for the car driver, but were absent
in this experiment. The research really demonstrates that, if most of the
natural perceptual information is absent, then drivers will use relative
size and hence misjudge the distance of a child.
In a natural setting, however, this may only happen for a one-eyed motorist,
with a very stiff neck, driving in total darkness with no road markings.
In this respect, the Department of Transport’s view of the research as ‘interesting’
but not confirmatory is correct. What is required is similar research with
visual environments where the driver has a realistic 3D visual scene that
responds to head motion, and where the display responds to the driver’s
progressive braking action (a feature also missing from the previous experiment).
Fortunately, virtual reality systems can now provide that facility; all
that is required is the DoT, insurance companies or other agencies to provide
the 拢100 000 or so that would enable such research.
John Wann University of Edinburgh
Letters: Murphy's Law
Your correspondent, Colin Morgan, (4 June) proffers an explanation
as to why toast falls butter side down when it is edged off the table under
rather special circumstances. In 1991 we broadcast a TV programme, ‘Murphy’s
Law’ on BBC1 in which we tested a variety of manifestations of
the law including ‘the other queue always moves faster, even if you change
queues.’
Using very careful statistical tests we could find no evidence for the
truth of Murphy’s Law. For example, the bread fell butter side up, 148 times
and down 152. But then we realised that Murphy’s Law was acting on our experiments
to frustrate them by arranging statistics so that it appeared that Murphy’s
Law did not hold.
To achieve success in any engineering venture it is best to assume Murphy’s
Law operates at all times: ‘If anything can go wrong, it will.’
Ian Fells University of Newcastle upon Tyne
Letters: Dissimulation
It is a deadly illusion of a different kind to believe that children
are killed on Britain’s roads because of an optical illusion. The reason
children are killed on our roads, particularly in residential areas of towns
and cities, is because car drivers drive too fast – 50 kilometres per hour
(otherwise 30 mph) is a ludicrous speed in narrow streets with parked cars
all around.
Peter Baker London
Letters: Hearing backwards
Yes, you could hear a V-2 coming after it had arrived (Letters, 25 June).
It was my good fortune, both from the points of view of my own personal
safety and Ernest Spratt’s curiosity, to be standing some distance from,
and perpendicular to, the flight path of a V-2.
It announced its arrival with its customary signature of a double bang
(bow wave followed by explosion) followed by a sound as of something shooting
away on a parabolic trajectory from the point of impact. This could have
only been the sound of the final stages of its journey to us, in reverse.
Instead of the usual double bang we had BANG, BANG, WHOOSH all in very
quick succession.
Ken Harrow West Wickham, Kent
Letters: Hearing backwards
The term ‘whizz-bang’ arose in the First World War, referring to guns
firing shells faster than the speed of sound. The recipient heard the whizz
of the shell before the bang of the gun.
Master Gunner Ian Hogg, in his brilliant ‘Barrage: The Guns in Action’,
which is part of Purnell’s History of the Second World War, points out that
it is possible to hear first the detonation of the shell, then the sound
of its arrival and finally the sound of the gun firing it.
N. R. Clitherow Gayton, Wirral
Letters: Hearing backwards
I, too, recall hearing this sound when a child and I remember the same
explanation being proffered afterwards. Though this seems plausible, I now
believe that there might be another, probably concurrent, mechanism.
In the course of experimental work, I frequently detonate charges of
high explosive weighing tens or a few hundred grams on, or directly above,
steel plates lying on the ground. If no solid debris is likely to be projected,
I usually observe the events from a distance of 20 or 30 metres, protecting
my ears with my hands.
As soon as I see the flash, hear the (attenuated) bang and feel the
blast, I remove my hands. Quite frequently (one in every hundred shots,
perhaps) I hear a sound varying from a metallic ringing to a whine or even
an apparently disembodied and rather eerie howl which sometimes lasts for
several seconds.
On such occasions I have frequently seen a smoke ring rising steadily
from the cloud of smoke still at ground level. Such a vortex, which sometimes
remains visible for tens of seconds, I suspect to be the generator of the
sound. The most favourable condition for the generation of such vortices
seems to be the detonation of an explosive charge in an open-ended, upright
pipe.
The characteristically deep conical crater of the fast V-2, as described
by Spratt, perhaps similarly favoured vortex formation. A smoke ring is
also frequently to be seen issuing from the muzzle of a large gun.
The energy contained in vigorous vortices is, I believe, considerable,
and, if not disturbed, may be retained for a surprisingly long time. On
one memorable occasion a couple of years ago, wishing to be rid of some
hundreds of kilograms of explosive, some old fuel oil and an old motor car
at the same time, I retired to a promontory about a mile away.
A splendid flash was followed by a generous bang. Though too far away
to hear any howl, I saw an enormous smoke ring rise to a few hundred feet
and drift slowly over my head where it became wobbly and dispersed some
four minutes later!
Sidney Alford Corsham, Wiltshire