Global syntheses of the evidence on urban and industrial productivity and education are
not very meaningful for the reasons given above. There are certainly studies which
show positive effects on productivity of education amongst urban workers in
developing countries (Fuller 1970, Berry 1980). Equally there are those that question
the strength and nature of such relationships and which show how widely such
correlations can vary across different types of job, from strongly positive to strongly
negative (Little 1984). Selectively citing those studies that support a particular
viewpoint would therefore be misleading. It should be noted however, despite the
mixed evidence, employers in many countries adhere to a set of beliefs which does
value explicitly educational attainment in the selection of employees. The research does
not suggest this is an unqualified judgement independent of job or job level. Moreover
there is evidence that employers often conceive of the problem in terms of minimum
levels of education suitable for different types of employment, above which other
factors may become more important in the selection of employees (Oxenham (ed)
1984:66). To the extent that this is generally the case it introduces the possibility of
curvilinear relationships between educational level and productivity, where it is
possible to be over educated and those with most education may produce less than those
with more modest attainments in particular jobs.
Knight and Sabot's (1990) work based on the "natural experiment" of comparing
samples of about 2000 employees in Kenya and Tanzania provides detailed insights
into education, employment and income relations in those two countries at the
beginning of the 1980's. Their findings support the human capital view that there is a
positive rate of return to investment in secondary schooling in both countries. More
specifically they argue that whereas the labour market returns to reasoning ability (as
measured by Raven's Coloured Progressive Matrices) are small, and to years of
schooling modest, the returns to cognitive achievement (as measured by numeracy and
literacy tests) acquired through schooling are large (ibid: 17). In Kenya cognitive skill
accounts for three times more variance in earnings than do ability and years of
schooling combined; in Tanzania the ratio is two to one. In neither country is being
amongst the brightest of one's peers a sufficient condition for performance in the labour
market - the predicted earnings of the most able primary completers are less than those
of less able secondary completers. In both countries how much is learned in primary or
secondary schools has a substantial influence on performance and income at work.
Moreover the evidence suggests a complementary relationship between cognitive skill
levels and returns on experience; the greater the former the greater the benefit from
experience and training over working lifetimes. Intriguingly, cognitive achievement
gains for secondary schooling for students of mean ability are 17 % higher in Kenya
than they are in Tanzania, despite the fact that per student expenditures are greater in
Tanzania suggesting there may be differences in the effectiveness with which resources
are allocated to teaching and learning (ibid: 23). Educational expansion also appears to
have led to compression of wage differentials over time contributing to a reduction in