I'm not sure they want to go with TIMSS here.
From the McKinsey report:
While Singapore does not participate in PISA, it ranked in the top three on math and science on the quadrennial Trends in International Mathematics and Science Studies assessments in 2007, after having come in first place in 1995, 1999 and 2003.from the National Center for Education Statistics:
In 2007, the average mathematics scores of both U.S. fourth-graders (529) and eighth-graders (508) were higher than the TIMSS scale average (500 at both grades). The average U.S. fourth-grade mathematics score was higher than those of students in 23 of the 35 other countries, lower than those in 8 countries (all located in Asia or Europe), and not measurably different from those in the remaining 4 countries. At eighth grade, the average U.S. mathematics score was higher than those of students in 37 of the 47 other countries, lower than those in 5 countries (all of them located in Asia), and not measurably different from those in the other 5 countries.