A MODEL TO CONTROL FOR THE BIASING EFFECTS OF DIFFERENTIAL WASTAGE*
| Published date | 01 November 1970 |
| DOI | http://doi.org/10.1111/j.1467-8543.1970.tb00586.x |
| Author | John Bibby |
| Date | 01 November 1970 |
RESEARCH NOTE
A MODEL
TO
CONTROL FOR
THE
BIASING EFFECTS
OF
DIFFERENTIAL WASTAGE*
JOHN
BIB BY^
Om
problem continually facing manpower strategists
is
that
of
using ‘snap-shot’
observations of the present to make valid inferences about the past. This prob-
lem has arisen during
a
current study
of
university teachers being undertaken
at
the Higher Education Research Unit
of
the London School
of
Economics.
Several writers have noted that recruits to the academic profession are less
well qualified than those who entered in the past, and gloomy prognostications
have been made concerning such evidence of ‘declining quality’.l There is,
however, no cause for gloom,
as
worse qualified teachers are more likely to
leave the profession,a and present-day stock therefore gives an upwardly biased
estimate of the quality
of
recruits in the past.
No
attempt has yet been made to correct
for
this bias, although the Robbins
Committee3 and Allan Cartter4 have given cautionary warnings
of
its dangers,
which stem from the fallacy
of
confusing stock with flow. The best procedure
would be to compare stock with stock, and ultimately this will be done at
H.E.R.U., using the Robbins Survey of 1963 and a similar one completed
during the current academic year. Meanwhile the mathematical model in the
Appendix can be used to correct stock figures for differential wastage, and thus
to compare flow with flow.
In the Appendix the Robbins figure of
44
per cent with ‘good’ first degrees
is shown to derive from
a
constant-quality entry
of
whom only
37
per cent were
‘good’. This is only slightly above the quality of post-Robbins recruits, when
allowance is made for increasing examination stringency, changes in subject-
mix,
and the incomplete coverage of U.G.C. Recruits data.5
We wish here merely
to
discuss certain limitations
of
the model in the
Appendix, and suggest possible directions for improvement.
*
The author would like to thank Mr Ingold
of
the University Grants Committee for help in
providing the data, and members of the Higher Education Research Unit
for
stimulating com-
ments on the project (on which this note
is
based) which
is
being conducted under funds provided
by the National Board for Prices and Incomes.
t
Research Officer, Higher Education Research Unit, London School
of
Economics and
.-
Political Science
National Board
for
Prices and Incomes, Report
No.
98,
Standing Reference
on
the
Pay
of
Universi& Teachers
in
Great Britain: First Report,
Cmnd
3866,
H.M.S.O., London,
1968,
p.
46,
para.
30;
and
A.
H. Halsey, ‘What about the Dons?’
New Statesman,
21
November
1969,
p.
724
a
N.B.P.I.,
op. cit.,
p.
46,
Table
9
Robbins Committee,
Report: Higher Education, Appendix III,
H.M.S.O., London,
1962,
’
Allan
M. Cartter, ‘The Supply and Demand for College Teachers’,Journal
of
Human
Resources,
1(1),
Summer
1966,
pp.
23-25
Gareth Williams, David Metcalf, John Bibby and Lydia Raine,
The Labour Market for
University
Teachers:
an
Interim Report,
Higher Education Research Unit, L.S.E., London,
1970,
p.
D9
418
p.
21
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