“If the teachers to be laid off were chosen in a way largely unrelated to their effectiveness, such as “last in first out,” then the associated increase in class size could well have a negative effect on student achievement. But if schools choose the least effective teachers to let go, then the effect of increased teacher quality could make up for some or all of any negative effect of increasing class size." (I debated Matt Chingos about class size on CNN here.)
State attorneys also have been arguing that larger class sizes in Texas – the result of a $5.4 billion funding cut by the Legislature last year – have not hurt students because class sizes don’t affect achievement. Whitehurst testified in support of that position. But again, under cross examination by Dallas lawyer John Turner, Whitehurst had to acknowledge that he wrote an article praising a well-publicized study of lower class sizes in Tennessee that found significant improvement in student achievement. Whitehurst explained that he had changed his mind since writing the article and now has doubts that class size has much impact on learning. In later testimony, he said he was being paid $340 an hour by the state to testify in the case, and had already racked up 220 billable hours – for just under $75,000 – before he took the witness stand.