school is considered as months of attendance rather than sessions per week as the EPPE
results clearly show an effect for number of months while 5 sessions are not significantly different
in their impact from 10 sessions a week. The various calculations on income and duration
effects show that for children in low income families, one extra year of pre-school (i.e. 3 rather
than 2 years) is associated with a similar effect upon pre-reading as increasing family income by
£10,000 p.a. The costs table overleaf show that any form of pre-school provision costs a lot less
than £10,000, particularly if only 5 sessions a week are provided.
Conclusion
The calculation of effect sizes for specific sub groups of children allows comparison with the
effects attributable to other child, family or home environment characteristics. Of particular policy
relevance for this paper are the comparisons with the size of family income effects and those of
different durations of pre-school. In addition the analyses reported here have extended the study
of the impact of different levels of quality and duration of pre-school.
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