Score Explanations
N
The number of students with valid test scores for the content area reported.
This is the number of students used for calculating the average scores reported.
Percentile Ranks
A percentile rank is the percent of people in the norming sample who had scores less than or equal to a student's score.
A student with a reading comprehension score at the 60th percentile scored as well or better than 60 percent of the students in the norming sample.
Stanford 9 is a nationally normed test.
The test was first administered to representative national crosssections of students in 1995.
There were Stanford 9 norming samples for each grade level that included students from all regions of the United States.
The samples were also representative of the nation in terms of ethnicity; urban, suburban and rural populations; socioeconomic status; large and small schools; and public, private, and Catholic schools.
Since the Stanford 9 norming sample was representative of the United States as a whole, it does not necessarily match California's student population.
Neither the test questions nor the scores reported have changed since 1995, so the achievement of California students tested during spring 2001 is compared to that of the 1995 national samples.
The SABE/2 is an achievement test in Spanish designed for students receiving instruction in Spanish reading, language, and spelling, as well as receiving mathematics instruction in Spanish.
The reference groups used for norming the SABE/2 were comprised of Spanishspeaking students in bilingual classes in 12 states including California.
Since the norming group was not a nationally representative sample of students, the percentile ranks are called "reference" scores rather than "national" scores.
Student scores are compared to the scores of students in the reference group in the same way that Stanford 9 scores are compared to the scores of a national sample of students.
NPR (National Percentile Rank) of the "Average" Student
For the STAR Program, Stanford 9 scores for individual students are reported as their percentile ranks.
There is no provision for producing group level, school or district, percentile ranks.
The percentile ranks of individual students cannot be used to produce an average percentile rank for a group, because percentile ranks cannot be added or averaged across students.
The national percentile rank of a hypothetical "average" student can be approximated by averaging the Normal Curve Equivalents (NCEs) for a group of students and then converting the average NCE to a national percentile rank.
Unlike percentiles that have unequal distances between them, NCE scores divide the normal curve into 99 equal parts.
The national percentile rank for the "average" student is an arithmetically derived scored that may not equal a score for any student in the group.
This is why the score is attributed to a hypothetical student.
RPR of the "Average" Student
RPRs of the "Average" Student for the SABE/2 are calculated in the same way that NPRs are calculated for the Stanford 9.
After calculating an average NCE for a group of students, the NCE is converted to a reference percentile rank.
% Scoring Above the 75th NPR, % Scoring At or Above the 50th NPR, and % Scoring Above the 25th NPR
These scores correspond to the percent of students in the school, district, county, or state with scores corresponding to those of students in the top quarter of the 1995 national sample (above 75th NPR), in the top half of the 1995 national sample (at or above the 50th NPR), and in the top threequarters of the 1995 national sample (above the 25th NPR).
The percent of students scoring above each level is calculated by counting the number of students above a particular NPR (76th NPR and higher) or at or above a particular NPR (50th percentile or higher) and dividing by the total number of students in the group to obtain a percent.
Note that the percent of students scoring at or above the 50th NPR is a subset of students scoring above the 25th NPR, and the percent of students scoring above the 75th NPR is a subset of the group scoring at or above the 50th NPR.
The percent of students scoring at or above the 50th NPR is the percent of students in this school, district, county or state with scores in the top half of the national sample.
These students are sometimes referred to as scoring at or above grade level.
To obtain the percent of students in the school, district, county or state that had scores in the lowest quarter of the national sample subtract the percent scoring above the 25thNPR from 100.
% Scoring Above the 75th RP, % Scoring Above the 50th RP, and % Scoring Above the 25th RP
These scores are similar to the NPR scores, except that the comparison group is Spanishspeaking students in Spanish bilingual classes.
Mean Scaled Score
Raw scores identify the number of questions answered correctly on a test or subtest.
Raw scores are limited in their measurement precision because of differences among test items and the number of items on each subtest.
A scaled score takes differences in the difficulty of items into account and is calculated to provide a more precise measure of the knowledge or skills tested.
Through this calculation, an increase of one point at one place on the scale is described as being equal to a onepoint increase anywhere else on the scale.
Scaled scores are particularly useful for reporting changes over time.
The Stanford 9 provides results in terms of scaled scores for individual students and mean or average scaled scores for groups of students.
The SABE/2 also provides scaled scores for individual students and mean or average scaled scores for groups of students.
Scaled scores can be compared within the same test, but not between two different tests.
That is the Stanford 9 scaled scores cannot be compared with the SABE/2 scaled scores.
The scaled scores should also not be used to compare two different content areas, such as reading and mathematics, on the same test.
Scaled scores for individual students or groups of students within each content area should increase each year, because both the Stanford 9 and the SABE/2 use a continuous scale from the lowest to the highest grade levels of the tests.
% of November Enrollment
Schools submit the number of students enrolled during November to the test publisher.
This number is used to determine the number of tests to send to each school.
The % of November enrollment is the number of students with valid test scores divided by the enrollment reported during November.
Performance Levels
Performance levels identify levels of student achievement based on a demonstrated degree of mastery of the content standards tested.
California uses five performance levels for its California Standards Tests:
 Advanced performance in relation to the content standards tested
 Proficient performance in relation to the content standards tested
 Basic performance in relation to the content standards tested
 Below Basic performance in relation to the content standards tested
 FarBelow Basic performance in relation to the content standards tested
The number and percent of students with California English Language Arts Standards Test scores at each performance level are reported for schools, districts, counties, and the state.
These scores are based on only the multiplechoice component of the standards tests.
The Grade 4 and 7 writing test results will be included in the performance levels beginning in 2002.
Performance levels will be adopted for the California Mathematics, Science, and HistorySocial Science Standards Tests during fall 2001 and will be used to report the 2002 test results.
