Nigerian students were from a higher grade than in other countries, and the Ghanaian
students were from selective and elite schools. The IEA data suggests that the bottom
20% of students in Ghana, Italy (Grade 8), Nigeria, the Philippines and Zimbabwe are
"scientifically illiterate". Interestingly England, Hong Kong, Singapore and the USA
are borderline cases. Indeed the USA has a higher proportion of schools scoring below
the worst school in Hungary than does Thailand.
Of particular interest is the finding that the teaching group or class that pupils are in is
of considerable significance to the scores that they achieve in some countries but not
others. This effect is particularly prominent in Ghana, the Philippines, Italy and the
Netherlands. By contrast in Japan and the Nordic countries at this level the effect is
very low indeed at the population 2 level. This changes dramatically in Japan at the
population 3 level, probably because of the increase in the proportion of private
institutions at this level. One of the implications of this appears to be that in some
countries differences between schools are considerable and it does matter a great deal in
which school or class students study science, in terms of their achievement. In other
countries, school and class effects are much smaller and have much less influence on
achievement. This is not simply a function of resource levels; rather it seems to depend
more on selection and streaming practices and organisational features of education
systems.
The IEA authors have developed a yield coefficient that modifies the distribution of
scores by the proportion of the age group in school. This is intended to indicate how
many children know how much science. It highlights differences between countries and
shows that yield coefficients tend to be much lower in those countries with the lowest
proportions in school which are mainly the developing countries at population 2 level.
This raises a dilemma for countries; with low yields wishing to improve them should
numbers enrolled be increased or should low levels of achievement be improved first?
At population 3 level in the IEA data inter-country comparisons are even more
hazardous than they are at population 2 level. There are wide disparities in the
percentage of the age group studying at this level from 1% in Ghana and Papua New
Guinea to 89% in Japan). The average age of this population spans 23 months. There
was a 2 year grade difference in the level which the tests were applied to. The average
number of subjects studied varied from 3 to 9 or more with concomitant variations in
the time spent on science.
Generally England, Singapore and Hong Kong and Hungary have the highest scores in
population 3 with some variations between subjects in this. These countries also have
small numbers enrolled and highly specialised curricula. In general the IEA found no
relationship between the proportion studying science and the achievement of elite
students defined as the top 3% of the age group. There was no significant tendency for
the number of subjects studied to influence science achievement except in Chemistry.