Despite the great number of papers published in recent decades
about the assessment of efficiency in education, the production function in
the sector is still unknown (Engert, 1996). There are several explanations
for this. Education is not an instantaneous thing but generates its effects in
the medium term; the output, which is multidimensional and difficult to measure, is the consequence of a complex process influenced by many
factors, some outside the control of the productive units.
This makes it extraordinarily difficult to define a general educational production function
that accurately includes all relevant aspects of the school production
process and, consequently, making it possible to measure efficiency
though a simple comparison between real results and those which could
potentially be achieved (Hanushek, 1986).