Introduction to Local and National Norms

The Naglieri General Ability Tests can be scored using local or national norms (see chapter 4, Scores and Interpretation, in the Technical Manual for more details about this scoring option). The Local Norms Report provides the results for a group of students that were tested in the same grade. The results are a direct comparison of any student in relation to all students in a specific school, district, or subdistrict. The National Norms Report provides a comparison to a student’s grade-peers within a nationally representative sample. It is important to note that the Local Norms Report should only be generated once all testing within a grade is completed.

Please watch the videos above for more information about local and national norms.

Understanding the Local Norms Sample

It is important to keep in mind that the composition of the local norm sample has a direct impact on the interpretation of the Local Norm Scores. Each student’s Local Norm Score is obtained by comparing their Raw Score to the scores obtained by students in the selected local norm sample (see chapter 4, Scores and Interpretation, in the Technical Manual for more information about how these scores are calculated and can be used). For this reason, it is important to ensure that all students within the selected grade have completed testing before the Local Norms Report is generated. Adding or removing one or more students in the local norm sample will affect the Local Norm Scores of all students within that report. Additionally, a student’s Local Norm Scores based upon individual schools will likely be different than their Local Norm Scores based upon a school district.

Best Practices for Local Norms

National and Local Norms

Equitable representation is influenced by the content of the tests used in the identification process (Naglieri & Otero, 2014), how the tests are used (Peters & Engerrand, 2016), and the definition of gifted and talented students. According to the National Association for Gifted Children (NAGC; 2019), “students with gifts and talents perform—or have the capability to perform—at higher levels compared to others of the same age, experience, and environment in one or more domains.” Comparing students to their peers of the same age or grade can be accomplished by using national or local norms. A national norm is created using a large sample of students who match the demographic makeup (e.g., in terms of age, sex/gender, race, ethnicity, parental educational level [a measure of socioeconomic status], and urban/rural settings) of that country (AERA, APA, & NCME, 2014). A student’s test performance is then compared to the test performance of students from that national norm. In a local norm, however, a student is compared to their peers in the school or school district. This scenario means the comparison group is more closely representative of the local community and its unique demographic makeup.

Most local norms compare a student to all students within the same grade in the same school, subdistrict (a subset of the district [e.g., Title I schools vs. Non-Title I schools]), or entire school district. This comparison represents the standing of a student to the local community. That is, the reference group is not limited in any way (e.g., only gifted students). “Local norms are often useful in conjunction with published norms, especially if the local population differs markedly from the population on which published national norms were based. In some cases, local norms may be used exclusively” (American Educational Research Association [AERA], American Psychological Association [APA], and National Council on Measurement in Education [NCME], 2014, p. 196). The Naglieri General Ability Tests allows Assessment Coordinators to generate both local and national norms so that decisions can be made in alignment with the local definition of gifted and talented and the needs of the individual school district.

When generating a Local Norms Report, the composition of the local comparison group is important. First, the sample used to create a local norm should be reasonably large (i.e., greater than 100 students) to ensure variability in responses, and second, it should adequately represent the local demographics. The local norm should also be inclusive and based on universal assessment of all students within a grade, not just those who have been previously screened in any way (e.g., a rating scale or teacher recommendation). For example, if the goal is to have a local norm for Grade 2 students, then all Grade 2 students should be tested.

The composition of the local norm sample can have a large impact on a student’s Local Percentile Rank, Local Stanine, Local Standard Score, and Total Local Score. Consider a local norm sample based solely on a group of students already in a profoundly gifted program. A small number of these students will obtain a Below Average score (less than the 15th percentile; see the figure below) in this sample; however, if these same students were compared to a local norm sample that included non-gifted students, they would all likely have a score in the Very Much Above Average range (above the 98th percentile). This difference in Local Percentile Rank is because Local Norm Scores are always relative to the other students in the sample. Therefore, it is strongly recommended that those interpreting these scores take note of who is included in the sample, especially when interpreting low scores on these tests.

Comparison of Score Types and Corresponding Categories

A student’s Local Norm Scores can be different when they are based upon an individual school, subdistrict, or district comparison. School-level Local Norm Scores indicate what score a student achieved in relation to the local school’s population, while subdistrict-level Local Norm Scores indicate what score a student achieved in relation to the population of a group of schools. The group of schools selected to comprise a subdistrict-level local norm generally include schools with a similar demographic makeup, such as Title I or Non-Title I schools grouped to define a subdistrict-level Local Norm. District-level Local Norms Scores indicate what score a student achieved in relation to the local district’s population as a whole. When a school or group of schools is more diverse or does not have the same representation as the district, then it can be more useful to examine the individual school or subdistrict norms to ensure a fair comparison of a student to their peers. In contexts where the school, subdistrict, or district’s population is diverse compared to national norms, local norms are useful for comparing a student’s score to one that more closely reflects students in the local community of learners.

The larger the local norm sample, the more precise the Local Percentile Rank, Local Stanine, Local Standard Score, and Total Local Scores will be. Ideally, minimum sample sizes should be about 100 students to calculate the Local Percentile Ranks, Local Stanines, Local Standard Scores, and Total Local Scores. When samples are smaller, it is recommended that the Local Rank Order be used, as it is unaffected by sample size.

The Naglieri General Ability Tests provide grade-based national norms for Kindergarten through Grade 5 computed by comparing a student to a nationally representative sample of students across the United States. National norms have the utility of comparing scores to a large sample size and are not dependent on the number of students or relative scores of the students tested locally. The National Norm Scores are calculated based on the grade of the student, and for Kindergarten and Grade 1, grade and age of the student, as these grade-levels include two distinct normative groups to reflect the moderate variability in ability with grade-peers in the younger students (see Table 4.1). Scores for students whose ages are outside of the typical range for a grade should be interpreted with caution, as the normative sample may not reflect their peers. See chapter 5, Development for detailed information on the normative grade groups.

Normative Groups for National Norms: Grades and Age Ranges

Normative Group	Grade and Age Range
Kindergarten–Lower	Enrolled in Kindergarten and 4 years 8 months to 6 years 1 month
Kindergarten–Upper	Enrolled in Kindergarten and 6 years 2 months to 7 years 10 months
Grade 1–Lower	Enrolled in Grade 1 and 6 years 3 months to 7 years 2 months
Grad 1–Upper	Enrolled in Grade 1 and 7 years 3 months to 8 years 11 months
Grade 2	Enrolled in Grade 2 and 5 years 0 months to 9 years 11 months
Grade 3	Enrolled in Grade 3 and 6 years 0 months to 10 years 11 months
Grade 4	Enrolled in Grade 4 and 7 years 0 months to 11 years 11 months
Grade 5	Enrolled in Grade 5 and 8 years 0 months to 12 years 11 months

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