Two groups of students, scoring higher and lower respectively in the PISA assessment of reading comprehension in March 2006, were tested on the same material in English 18 months later.
Geta tveggja nemendahópa, slakari og sterkari hópa samkvæmt 2006 PISA mælingu á lesskilningi, var borin saman 18 mánuðum seinna þegar sama efni var lagt fyrir á ensku.