In response to today's Times piece on in-classroom ability grouping, I blogged over at Slate about the potential tensions between "high expectations" and "differentiation," two of the education world's favorite buzzwords. The comments section is rollicking, with many Slate parents supporting pull-out gifted and talented instruction. Among teachers participating in the discussion, there seems to be some disagreement about whether the optimal classroom groupings are static or flexible. One teacher supports stable groups that include one child great at math, another strong in reading, another who is an avid artist, etc. Another says classroom groups should never be static; continuous assessment means students can move into an advanced group on a given subject when they grasp a new concept, providing a sense of accomplishment.