{"id":91,"date":"2011-06-20T16:08:48","date_gmt":"2011-06-20T21:08:48","guid":{"rendered":"https:\/\/horizon-research.com\/atlast\/?page_id=91"},"modified":"2026-06-01T18:29:40","modified_gmt":"2026-06-01T18:29:40","slug":"page34-2","status":"publish","type":"page","link":"https:\/\/horizon-research.com\/atlast\/?page_id=91","title":{"rendered":"Evidence of Reliability and Validity"},"content":{"rendered":"<p>The ATLAST student assessments have strong evidence of reliability and validity.<\/p>\n<h3>Reliability<\/h3>\n<p>Using data from the final field test, the internal reliability of each assessment was calculated using both a classical approach (Cronbach&#8217;s alpha) and Item Response Theory (IRT).\u00a0 The IRT internal reliability for each student assessment is given below:<\/p>\n<ul>\n<li>Flow of Matter and Energy:\u00a0\u00a0 .78<\/li>\n<li>Force &amp; Motion:\u00a0\u00a0 .75<\/li>\n<li>Plate Tectonics:\u00a0\u00a0 .86<\/li>\n<\/ul>\n<p>The Cronbach alphas were similarly high.<\/p>\n<h3>Validity<\/h3>\n<p>Three lines of evidence support the argument that the assessments are valid measures of students\u2019 knowledge of force and motion ideas. First, cognitive interviews with students (see <a href=\"https:\/\/horizon-research.com\/atlast\/?page_id=69\">Writing Items and Cognitive Interviews<\/a>) established that students interpret the items as intended and that students must use their knowledge of content to answer the items correctly. Second, a panel of three content experts (e.g. individuals with a Ph.D. in physics) reviewed the assessment items (see <a href=\"https:\/\/horizon-research.com\/atlast\/?page_id=75\">Expert Review<\/a>) at three stages (see <a href=\"https:\/\/horizon-research.com\/atlast\/?page_id=82\">Student Assessment Development<\/a><a>)<\/a> to ensure content accuracy. They also reviewed the final assessment and judged it to be an adequate measure of the content domain.<\/p>\n<p>Finally, dimensionality analyses (including both factor analysis and cluster analysis) indicate that all items on the Plate Tectonics and Flow of Matter and Energy assessments measure a single dominant trait. HRI termed this trait &#8220;content knowledge.&#8221;\u00a0 These analyses indicate that both a both a 1-factor and a 2-factor solution were supported for the Force and Motion assessment.\u00a0 We chose the 1-factor solution, with all items on the assessment measuring\u00a0&#8220;content knowledge&#8221; as a \u00a0single dominant trait.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The ATLAST student assessments have strong evidence of reliability and validity. Reliability Using data from the final field test, the internal reliability of each assessment was calculated using both a classical approach (Cronbach&#8217;s alpha) and Item Response Theory (IRT).\u00a0 The&hellip; <\/p>\n","protected":false},"author":2,"featured_media":0,"parent":89,"menu_order":32210,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-91","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=\/wp\/v2\/pages\/91","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=91"}],"version-history":[{"count":3,"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=\/wp\/v2\/pages\/91\/revisions"}],"predecessor-version":[{"id":666,"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=\/wp\/v2\/pages\/91\/revisions\/666"}],"up":[{"embeddable":true,"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=\/wp\/v2\/pages\/89"}],"wp:attachment":[{"href":"https:\/\/horizon-research.com\/atlast\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=91"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}