Have mathematics and science education’s curricular visions and textbooks changed so
quickly that the current data are no longer valid? The TIMSS data on teacher practices discussed
here were collected in 1995. The fact that these data agree so well with earlier data on curricula
and textbooks suggests that, whatever changes occur at the level of “intended” (planned for,
envisioned) curricula, changes in “implemented” (actual classroom practice) curricula lag
somewhat behind (assuming, perhaps optimistically, that what we intend in time affects what is
practiced).