Misunderstanding Rigor

I just read a new report from the Department of Education.  As the article from Education Week notes,
"We’re actually seeing [states] increase the rigor of their cut scores, at least between 2007 and 2009,” Jack Buckley, the commissioner of the National Center for Education Statistics, said during a conference call with reporters. “That doesn’t fit into the narrative of states lowering their bars” in response to the performance pressures of the No Child Left Behind Act. Using the National Assessment of Educational Progress as a common yardstick, the analysis finds that during the 2007 to 2009 time period, eight states raised the cut score—the level students must reach to be deemed “proficient”—on one or more exams, while two states lowered them.

So in this case, rigor means raising the passing score on standardized testing.  The main question I'm asked by teachers is "what does rigor mean"?  Although the word is used in many ways, when it comes to your classroom, remember:
Rigor is creating an environment in which each student is expected to learn at high levels,
each student is supported so he or she can learn at high levels, and each student demonstrates learning at high levels (Blackburn, 2008).