The Iowa Tests of Basic Skills (ITBS) are standardized tests provided as a service to schools by the College of Education of The University of Iowa. The tests are administered to students in grades K-8 as part of the Iowa Statewide Testing Programs, a division of the Iowa Testing Programs (ITP). Developers E. F. Lindquist, Harry Greene, Ernest Horn, Maude McBroom, and Herbert Spitzer first designed and administered the tests, originally named the Iowa Every Pupil Test of Basic Skills, in 1935 as a tool to improve instruction. Over decades, participation expanded and currently nearly all school districts in Iowa participate annually in the program, as do many other school districts nationally. In a cooperative relationship, participating schools receive ITBS test materials, scoring and reporting services and consultation in the use of ITBS for instructional purposes, and ITP utilizes participation by schools in research and test development.

ITBS are written in levels 5-14, which generally correspond with grade levels (K-8). Each test level consists of a series of tests administered in content sections with each section designed to measure specific skills. Test levels 5-8 are administered to students from kindergarten through second grade (K-2). School districts employ the series of tests in primary grades to gain information about classes and students for instructional planning, to supplement teacher observations regarding student abilities, and to establish a basis for subsequent annual evaluation of student progress. Sections for levels 5-8 include: Vocabulary, Word Analysis, Reading Comprehension, Listening, Language, Mathematics, Social Studies (Levels 7 and 8 only), Science (Levels 7 and 8 only), and Sources of Information (Levels 7 and 8). 

Test levels 9-14 are administered to students in grades 3-8. Like test levels 5-8, the primary purpose of levels 9-14 is instructional development. School districts use the standardized achievement battery to learn supplementary information useful in choosing curriculum and lesson planning. Teachers may use ITP testing batteries to suggest areas where the skills of individual students are most and least developed. Sections for levels 9-14 include: Vocabulary, Reading Comprehension, Spelling, Capitalization, Punctuation, Usage and Expression, Math Concepts and Estimation, Math Problem Solving and Data Interpretation, Math Computation, Social Studies, Maps and Diagrams, Reference Materials, Word Analysis (Level 9 only), and Listening (Level 9 only). Iowa Testing Programs informational material includes content discussing the application of testing and testing results and lists some appropriate and inappropriate purposes for testing in lower primary and upper primary and middle school grade levels. Testing services report scores for ITBS in a variety of forms, and ITP provides explanations of each form and how to match individual forms with their corresponding contexts for interpretation. Types of scores include: Raw Scores (RS), Percent Correct (PC), Grade Equivalent (GE), Developmental Standard Score (SS), and Percentile Rank (PR). School districts in Iowa receive scoring information using both national and state-specific data. When the ITBS are taken along with theCognitive Abilities Test, the test report additionally compares the student's results to his or her predicted scores.