At http://nces.ed.gov/nationsreportcard/ITMRLS/, the National Assessment of Educational Progress lets you search for sample selected-response science items that can be browsed for usability. Also, the Web site known as Performance Assessment Links in Science (http://pals.sri.com/) has 17 performance assessment tasks at the high-school level. The tasks assess student understanding of content and processes regarding cells, ecosystems, physiology, and genetic traits. These tasks have been developed and administered by state departments of education, school districts, universities, and research institutes.