1997-98 Knowledge and Concepts Examination Data

IV. UNDERSTANDING THE DATA

The WSAS Knowledge and Concepts Examinations are comprised of a battery of achievement tests which provide data that generally are collected under standardized conditions. For the first time this year, the data for a particular school or district are reported in terms of the percent of students enrolled in the school or district for a full academic year who have achieved at each proficiency level. The reported percentages for the four proficiency categories are based on the total enrollment in the fourth grade for a full academic year. Students who did not participate in the WSAS examinations were reported under a separate category ("Not Tested on WSAS"). In addition to the proficiency data, this report includes a normative score, the percentile rank of the mean normal curve equivalent. This score allows comparison of the results of students in Wisconsin with those of a representative sample of a national norm group.

The statewide proficiency scores reported in this report are for "all students" enrolled. Normative scores are based on "all students" tested. The test questions are presented in an integrated fashion and reported by content rather than by question type (multiple choice, short answer). Writing scores are scaled with the language arts scores and both are reported together as an enhanced language score.

Data for each reporting level (state, district, and school) are presented as follows:

• Number Enrolled Grade shows the number of students indicated by the school at time of testing as being enrolled in the grade. The number of enrolled students reported by the school should be very close to the "third Friday count in September" that districts submitted to DPI for state aids.
• Number Included in %s shows the percent of students who are included in the score distribution. Results for student groups in the "Disaggregated Results" section must be interpreted with caution. Enrollments and percentages reported for a student group in this section may include either all or some of the students in the group who are enrolled. All of the students will be reported when student privacy will not be violated. Otherwise, only some of the students are reported, as explained below.
  Care was taken to maintain student confidentiality and avoid disclosure of test results for small numbers of students, either directly or indirectly. Indirect disclosure occurs when results are reported for all students in a group and a large subset of this group, leaving only a small subset not reported. Thus, where five or fewer students are in a subset of a larger group such that there is a risk of identifying an individual student, the test results for this subset are merged, where possible, into the next larger subset of the larger group, or not reported at all. While this approach does reduce the meaningfulness of certain reportable school-level results, it is necessary to honor individual pupil confidentiality.
  Computerized data suppression formulas were used to report results for as many students as possible in each subset without violating student privacy. Enrollments reported in the "Disaggregated Results" section of this report are for students in each subset whose results were included in computing percentages. For many categories of students, this will be identical to the number enrolled in the category. For other categories, it will be some, usually most but not all, of the students. If it was not possible to report any results without violating privacy, then the enrollments are reported for all students in the category.
  For the purposes of this report, the following proficiency summary results are provided for each content area, based on the total enrollment. The percentages in these summary results under all five categories represent the total group and, therefore, add up to 100 percent.

• % Not Tested on WSAS shows the percent of students who did not participate in the assessment because they were absent and did not make up the test, disabled, not proficient in the English language, or excused by parents or guardians from taking the test.
• % Minimal Performance shows the percent of students who scored at the MINIMAL PERFORMANCE level. This level indicates limited achievement with evidence of major misconceptions or gaps in the knowledge and skills tested.
• % Basic shows the percent of students who scored at the BASIC proficiency level. This level indicates some competence in the content area including mastery of most of the important knowledge and skills. Test score indicates evidence of at least one major flaw in understanding the academic content area tested.
• % Proficient shows the percent of students who scored at the PROFICIENT level. This level indicates competence in the content area including mastery of the important knowledge and skills. Test score shows evidence of skills necessary for progress in the academic content area tested.
• % Advanced shows the percent of students who scored at the ADVANCED proficiency level. This level indicates performance that is distinguished in the content area with achievement beyond mastery. Test score provides evidence of in-depth understanding in the academic content area tested.

In addition to the proficiency scores, this report includes the national percentile rank in each content area for the state, districts, and schools.

• National Percentile Rank. The national percentile rank of the mean normal curve equivalent (NP of the mean NCE) indicates the relative standing compared with others in the same grade in the norm (referenced) group. Percentile ranks range from a low of 1 to a high of 99, with 50 denoting average performance for the grade. A percentile rank may be interpreted as the percentage of students in a norm group who obtained scores equal to or lower than a given student's scale score. For example, if a district average scale score converts to a national percentile rank (NP) of 71, that means that the average student in that district scored as well as or higher than approximately 71 percent of the students in the national norm group. The average percentile rank for a student in the national norm group is 50.
  Note that percentile ranks are not equal-interval data; differences between percentile ranks are larger near the ends of the range than they are in the middle. Therefore, they are not suitable for research purposes. The NCE score is generally used for research purposes. It enables researchers to manipulate test data in various ways because of its equal-interval nature. There is a direct, fixed relationship between percentile ranks and NCEs, as explained and shown in the following table.

NORMAL CURVE EQUIVALENT CORRESPONDING TO NATIONAL PERCENTILE RANK TABLE

NOTE: The NCE scores are generally used to compare scores across the content areas tested. The NCE scale ranges from 1 to 99 units. It coincides with the national percentile scale at points 1, 50, and 99. NCEs have many of the same characteristics as percentile ranks, but have the additional advantage of being based on an equal-interval scale. The difference between two successive scores on the NCE scale has the same meaning throughout the scale. This property affords an opportunity to make meaningful comparisons between different achievement tests within the same battery. NCEs obtained by different groups of students on the same test or tests may be compared by averaging the scores for the groups.

For questions about this information, contact dpistats@dpi.wi.gov (608) 267-3166

Last updated on 12/15/2011 4:12:14 PM