Frequently Asked Questions about the Iowa Test of Basic Skills (ITBS)
What type of test is the ITBS?
The Iowa Test of Basic Skills (ITBS) is a nationally standardized, norm-referenced test (NRT).
What does “nationally standardized” mean?
A nationally standardized test is a test that each student is administered in the same way across a specific reference population such as by age, grade level, etc. Therefore, the score interpretations are based on a comparison of the student’s performance to the performance of other students in the nation.
What is a norm-referenced test (NRT)?
It is a NRT because it compares students ‘abilities rather than to a criteria. Therefore, the ITBS allows our staff to get a look at the performance of our students in relation to the rest of the nation. A NRT is designed to highlight achievement differences between and among students.
How valid and reliable is the ITBS?
The ITBS was developed at the University of Iowa in 1935, and has been consistently developed and reevaluated through nationwide use over more than 70 years.
What does the ITBS measure?
The ITBS measures the skills and achievement of students from kindergarten Through 8 objectives. It also yields reliable and comprehensive information both about the development of students’ skills and about their ability to think critically. It measures students against their peers. Test subjects in the ITBS are in reading, language arts, mathematics, social studies, and science. The ITBS is also aligned with the national Common Core standards.
What types of results does the ITBS give on the student report?
The ITBS produces national standard scores (NSS) (i.e., scaled scores), national percentile ranks (NPR), and national stanine (NS).
What does the national standard score (NSS) mean?
The national standard score (NSS) is a number that describes a student’s location on a scale. The standard scores correspond to average performance (mean) of grade groups on the ITBS in the spring of the school year.
What is a national percentile rank (NPR) score?
A national percentile rank score compares the achievement of a student or a group of students to the achievement of a national sample of students who are in the same grade who were tested at the same time of the year (for CLS students it is in the spring). For example, if a student earned a percentile rank of 72 on the science test, it means she scored higher than 72 percent of the students in the group with which she is being compared.
What is a national stanine (NS) score?
National stanines are normalized standard scores that range from 1 to 9 (with 9 being the highest) and have an average value of 5. They also can be considered groupings of percentile ranks, as the table below shows:
Percentile Rank: 1-4 5-11 12-23 24-40 41-59 60-76 77-88 89-95 96-99
Stanine: 1 2 3 4 5 6 7 8 9
What is the “Core Total” score?
The Core Total score is the average of the Reading, Language and Mathematics test
scores. The tests cover the following areas:
- Reading: Vocabulary + Reading Comprehension
- Language: Spelling + Capitalization + Punctuation + Usage/Expression
- Mathematics: Concepts/Estimation + Problem Solving/Data Interpretation + Computation
What is the “Total Composite” score?
The Total Composite score is the average of the Reading, Language, Mathematics,
Social Studies and Science test scores.
- Total Composite: Reading + Language + Math + Social Studies + Science
What is the CogAT?
The CogAT is the Cognitive Abilities Test, which measures both general and specific cognitive abilities. The general reasoning abilities measured by the test show the cognitive process and strategies that help a student learn new tasks or solve problems. This test measures developed abilities, not innate abilities. The CogAT measures learned reasoning and problem-solving skills in three different areas: verbal, quantitative, and nonverbal. It is not considered a measure of achievement.
The verbal section has three subtests, which focus on reasoning skills, flexibility and fluency. It includes subtests on verbal classification, sentence completion and verbal analogies. The quantitative section tests the child’s understanding of basic quantitative concepts and relationships that are essential for learning mathematics. It includes sub tests on quantitative relations, number series, and equation building. The equationbuilding test looks at a students’ ability to organize, structure and give meaning to an unordered set of numerals and mathematical symbols. The non-verbal section uses geometric shapes and figures. This section helps us see how students look for shapes and patterns. A separate score is reported for each of these three areas. A composite, or total, abstract reasoning score is also reported. Reasoning abilities have substantial correlations with learning and problem solving, both in and out of school.