control
– affected performance more than the typical resources of schools
such as the number of teachers, class sizes or the school costs.
The publication of this report led to a wide
-ranging deba
te between
those who hold that these factors have no influence on educational results
(Hanushek, 1986) and those who believe that spending more on education
produces better results (Pritchett and Filmer, 1999).
In any case, a study
which aims to measure th
e productive efficiency of a group of schools
must also consider these productive factors, since in the concept of
technical efficiency is implicit the idea of how well resources are used.
The case of exogenous or environmental variables, which are
common
in other productive sectors, is different. Their influence on school
output has been widely confirmed by empirical evidence and it is usually
associated with a specific producer characteristic which may affect results
(Pedraja and Salinas, 1996).
Examples
in the educational sector are the
type of ownership of the schools (public or private) or their location (urban
or rural).
In these circumstances, the usual solution is to group units and
compare them with those operating in a similar environment.
On the
other hand, the representative variables of pupil
characteristics,
which are also sometimes considered as exogenous
, are
inputs which have a direct effect on the productive process and influence
the results. These inputs, which the units cannot control (n
on
-controllable
inputs), should be considered in the efficiency evaluation so that those for
which the educational centres are responsible can be calculated.
However, public data about these variables are not usually
available, thus simple proxies for them are used in many studies
. One way to overcome these limitations, although costly and therefore
infrequently used, is to conduct surveys of pupils in order to obtain