This paper uses an approximate average percent-correct methodology to compare the ranks that would
be obtained for PISA 2006 countries if the rankings had been derived from items judged by each country to
be of highest priority for inclusion. The results reported show a remarkable consistency in the country rank
orderings across different sets of countries’ preferred items when comparing with the rank reported in the
PISA 2006 initial report (OECD, 2007). On average, only few countries systemically go up or down in
their ranking position. As these countries are in a group of moderate performers with very comparable
outcomes, these shifts in the ranking would probably be associated with minor changes in mean
performance on the final PISA scale. The analysis suggests that PISA rankings are noticeably stable thanks
to the large enough pool of test items able to accommodate diverse preferences. The paper shows how
important it is to base a choice of test items on a properly structured process which allows different experts
and countries to equally contribute. The evidence presented demonstrates that in PISA, average rank
positions of countries across different sets of preferred items are apparently stable and experts are not able
to predict which items can elevate performance of their countries in the final test.
