Students undergo regular assessments, in the form of exams and school assignments, to evaluate their reading ability, but diagnostic tests can help teachers make grade-level comparisons and determine the need for interventions. The Stanford Diagnostic Reading Test -- or SDRT -- is a research-based assessment that teachers and other school staff can use to evaluate a student's literacy level from kindergarten through high school.
Beginning With the Basics
Before judging the reliability of the SDRT, you must understand what the test is and why educators use it. It assesses students' reading skills, including the areas of phonemic awareness, phonics, vocabulary, fluency and comprehension. The test includes multiple-choice questions that evaluate a student's abilities in reading-related areas. Unlike a multi-subject assessment, the SDRT doesn't evaluate a student's overall academic performance or rate developmental milestones.
The Standford Diagnostic Reading Test is a norm-referenced assessment, weighing a student's scores against norms for grade-level reading. For this purpose, the SDRT is considered reliable. However, if you want to review a student's reading abilities in relation to another group -- such as children in the next grade up -- the test's reliability isn't certain. For the test's scoring to be reliable, you must view results from the same grade level.
The SDRT is not the only diagnostic or screening evaluation available to educators. Other reading assessments include previous versions of the SDRT, the Woodcock Diagnostic Reading Battery and the Gray Oral Reading Diagnostic Test. Additionally, some other assessments include all or multiple areas of learning, such as the Otis-Lennon School Ability Test. The Kentucky Collaborative Center for Literacy Development notes that the SDRT -- in the fourth edition -- has roughly the same reliability as the SDRT3 -- the third edition of the test -- and the Otis-Lennon School Ability Test.
Judging the SDRT's reliability also must take into account specific state or national standards regarding what students should learn and master. Understanding reliability in light of language arts standards can help gauge the consistency of the grade-level evaluation. The Kentucky Center for Literacy Development notes that the evidence points to the SRDT as appropriately aligned with many state standards as well as the national Common Core Standards.