In addition to the assessments, field tests, and pilot tests, the National Assessment of Educational Progress (NAEP) includes special studies. These studies typically seek to expand knowledge about student achievement topics that the standard NAEP assessments are not designed to address or to test new types of cognitive items and innovative features. For example, NAEP conducted a special study of the effectiveness of online test delivery systems in its 2001 mathematics online and 2002 writing online studies which were instrumental in the introduction in 2009 of a computer-based science assessment.