Accountability policy has been controversial. Some assert that the new policy has distorted school decisions in undesirable ways, such as leading to higher drop-out rates, more cheating on tests, and undesirable narrowing of what is taught, although evidence on these effects is currently limited. Another charge is that it has prompted schools to weed out poor achievers by placing more students in special education classes - those for the educationally handicapped - and thereby improve the regular achievement score for the school and its classes, regardless of efforts to upgrade actual teaching. The Hanushek-Raymond study finds no such effects at the state level. Between 1980 and 2001 the proportion of students assigned to special education classes rose from 10 percent to over 13 percent. But this trend, one going on for two decades now, was not altered by the introduction of accountability across states in the 1995-2000 period.