From a press release announcing the publication of the report:
Grubb and Oakes conclude that this current push for “rigor” fails on several levels. The reports [proposing that high school be "reinvented"] don’t adequately consider the likely consequences of the policies intended to enforce higher standards. They also “have little to say about how [the] imposition [of these standards] will enhance student performance.” And most discussions in these reports focus on narrow definitions of rigor--higher test scores, more demanding courses, or both--while ignoring other conceptions of rigor that may be as valid, if not more so, to discussions of how high schools should better fill society’s needs.
Rigor, the authors explain, can also be advanced as depth rather than breadth, as more sophisticated levels of understanding including “higher-order skills,” and as the ability to apply learning in unfamiliar settings. These goals are largely neglected in the new “high standards” commission reports.
You can find it here.