Educational Research - the Ethics and Aesthetics of Statistics

104 E. Hemelsoet
definitions are used and again it should be stressed that policy differences cannot
be overcome. Some figures are even calculated on the basis of extrapolation of the
number of irregular migrants that reached their destination countries by looking at
the number of migrants arrested at the borders. Based on discussions with border
control authorities, a multiplier is defined (for example, multiplying 60,000 border
apprehensions in 1993 multiplied by 4–6, cf. Widgren, 1994). Estimations then
hardly seem to be more than mere ‘guesstimates’ as they are to a large extent based
on ungrounded assumptions. Moreover, with international comparisons, there are
always added difficulties when comparing the different datasets as they measure different
things, using different systems, at different times and by different authorities
(Clarke, 2000).
This does not keep researchers from drawing remarkable conclusions. It is recognised
that ‘the review of efforts to estimate the size of irregular migration on a
European level has shown that the numbers indicated are based on very rough
estimates’ because ‘often we do not know which groups of irregular migrants are
included in a stock estimate, nor do we know whether a flow estimate is meant to
measure net inflows or gross inflows’ and ‘older studies are often quoted in newer
studies, so that estimates appear to apply to the present, although they were made
some years ago’ (Iglicka, in Kraler & Vogel, 2008, p. 17). Still, researchers say
that ‘approximate comparability is better than no data at all in a situation where a
high degree of comparability may never be achieved’ (Vogel & Kovacheva, 2008,
p. 17) or that ‘these estimates will greatly aid policy making’ (IPPR, 2006, p.9).
Reference is made to policy: ‘In the public sphere, there is a general need to gather
reliable information on important social phenomena, to determine whether or not
the situation warrants any political action. [...] For governments, the perceived size
of the phenomenon will have an important bearing on the justification for the expenditure
of public resources on alternative uses’ (Jandl, 2004, p. 152). The idea that
‘approximate comparability is better than no data at all’ seems to count here as well.
Given the far-reaching consequences at policy level, glossing over the large
and to a great extent insurmountable problems that are related to estimating
irregular migrant numbers is highly problematic. Or as Clarke (2000, p. 21)
states
... whichever method of assessment is used, estimated numbers of irregular migrants are
based on assumptions, many of which are either untested or maybe even untestable. The
fact remains that unrecorded and irregular migration is, by its very definition, unquantified
and, indeed, unquantifiable. Any figure generated is at best an educated guess. [...] And yet
there are many pressures from policy makers, the media and other interest groups to come
up with a quotable figure. When an estimated figure is ‘calculated’ no matter what warnings
and disclaimers are attached to it, as has been seen a number of times in the last few years
of growing interest in trafficking and ‘illegal’ migration, there is a danger that this figure is
picked up and rapidly circulated and, before long, quoted as a fact.
The nature of Clarke’s critique is clear, and goes beyond concrete problems
related to particular methods. From a scientific perspective, there is a lack of reliability
in the estimations obtained. To a certain extent, the phenomenon of irregular