The outstanding improvements in Israel’s rankings in international tests for schoolchildren that the Education Ministry celebrated on Tuesday were achieved through manipulation, as students from Israel’s weakest sectors academically were not tested, critics are charging.

Israel made its most significant progress in decades in the PIRLS and TIMSS tests — jumping 17 spots in math, 12 spots in science and 13 spots in reading, while most other countries remained in more or less the same positions as in previous tests — with Education Minister Gideon Sa’ar crediting traditional Jewish values and organizational reforms.

Late Tuesday night and early Wednesday morning, however, another factor was revealed: nearly one-quarter of the country’s students were withheld from the exams. Further, the students withheld from the international tests came from the Haredi independent schools and from schools defined by the state as “special education.” These sectors, together with the Arab sector, are traditionally the country’s weakest performers in such tests.

The figures, as reported by the testing agencies (here, here and here), show that Israel is far above the average for percentage of pupils not taking the tests — two to three times more than the next highest countries. For instance, in the TIMSS eight-grade math test, 22.6 percent of Israeli students eligible to take the test did not do so.

Former education minister Yuli Tamir was quoted by several media outlets late Tuesday as saying that Israel’s results in the PIRLS and TIMSS tests were unreliable and not a true assessment of the country’s education system. Other past and present education officials — some unnamed — suggested that the figures had been manipulated to show progress that does not exist in reality. They also complained that the improvements in math, science and reading scores came at the expense of teaching hours and other resources that had previously been devoted to subjects such as Jewish studies, Israeli history and geography.