Technical Summary for Form F of the Iowa Assessments

Technical Summary for Form F of the Iowa Assessments ITP Research Series Catherine J. Welch Stephen B. Dunbar Anthony D. Fina ITP Research Series 2018.1

Iowa Testing Programs endorses the Code of Fair Testing Practices in Education and the Code of Professional Responsibilities in Educational Measurement, guides to the conduct of those involved in educational testing. Copyright 2018 by The University of Iowa. All rights reserved.

Description of the 2017 Norming Process The Iowa Assessments, Forms E, F and G comprise the most current edition of an achievement test series developed by the University of Iowa. The assessments measure student achievement in reading, mathematics, language, science, and social studies. Results of the Iowa Assessments are reported in several metrics designed to support a variety of interpretations including growth and relative comparisons. The National Percentile Rank (NPR) metric indicates the status or relative rank of a student s achievement compared with that of a nationally representative sample of students. This metric makes it possible to chart educational progress over time, providing a basis for examining changes in national performance. The most recent NPRs for the Iowa Assessments are based on studies conducted in 2011 through 2017 in which national samples of public and private school students were assessed in all content areas. As a result, information from the Iowa Assessments allows educators and parents to compare individual students or groups of students to the most current estimate of national performance available. The procedure used to obtain 2017 norms for the Iowa Assessments was designed to yield upto-date normative interpretations of test performance that closely reflect the performance that would be expected from participants in a national standardization in the years after the standardization took place. Important components of the process are the selection and weighing of schools that are used to determine the average degree of change in performance over time, and the method used to estimate change. The target population for establishing 2017 norms was that set of school districts across the United States with regular patterns of testing beginning in the fall of 2011. A regular pattern of testing means administration of the Iowa Assessments in two consecutive years at a common set of grade levels. Schools that did not have at least two consecutive years of test data, or that tested in one set of grades one year and another set the following year, were not included in the analyses on which 2017 norms were based. After schools that satisfied the criteria for selection were identified, sampling weights were determined by assigning each district a nominal weight of 3 and then up-weighting or downweighting systematically until the difference between the weighted sample and the population targets were minimized. The weighted distributions of student records matched the targets set from the 2015-2016 Common Core of Data (CCD, National Center for Education Statistics, downloaded from https://nces.ed.gov/ccd/) for the 2017 national norms in terms of the principal stratification variables, that is, geographic region, Title I status and district size. The states that belong to each geographic region are provided below. Northeast Midwest South West (CT, ME, NH, RI, VT, NJ, NY, PA, MA) (IL, IN, MI, OH, WI, IA, KS, MN, MO, NE, ND, SD) (DE, DC, FL, GA, MD, NC, SC, VA, WV, AL, KY, MS, TN, AR, LA, OK, TX) (AZ, CO, ID, MT, NV, NM, UT, WY, AK, CA, HI, OR, WA) 1

The representation of students in the public and private school population described above was proportional to the representation of districts in the 2011 national standardization population. These percentages are reported in Table 1, which reflects the fact that sampling weights were established for the private school portion of the norming samples separately so that the percentages of private school students matched the population targets. The complete results of the weighting procedures are provided in Tables 2, 3 and 4 for the public school portion of the norming samples. Information for the private school samples are provided in Tables 5. Table 1: Percentage of Students by Type of School, Grades 1 12 Iowa Assessments Form E Fall 2017 National Comparison Study Type of School Percentage in Weighted Sample Percentage in Population* Public Schools 90.0 91.7 Catholic Schools 4.4 3.9 Private (Non- Catholic) Schools 5.6 4.4 Total 100.0 100.0 *Totals may not equal 100.0 due to rounding. Table 2: Percentage of Public School Students by Geographic Region, Grades 1 12 Iowa Assessments Form E Fall 2017 National Comparison Study Geographic Region Percentage in Weighted Sample Percentage in Population* Northeast 16.7 16.4 Midwest 26.8 21.2 South 32.4 37.7 West 24.1 24.9 *Totals may not equal 100.0 due to rounding. 2

Table 3: Percentage of Public School Students by Title I Status, Grades 1 12 Iowa Assessments Form E Fall 2017 National Comparison Study Title I Status Percentage in Weighted Sample Percentage in Population* Title I (Schoolwide) Title I (Non- Schoolwide) 55.1 55.5 12.0 15.7 Non-Title I 32.9 27.8 *Totals may not equal 100.0 due to rounding. Table 4: Percentage of Public School Students by District Enrollment, Grades 1 12 Iowa Assessments Form E Fall 2017 National Comparison Study District K 12 Enrollment Percentage in Weighted Sample Percentage in Population* 50,000 100,000+ 23.9 18.3 25,000 49,999 13.2 13.6 10,000 24,999 24.3 18.6 5,000 9,999 4.1 14.8 2,500 4,999 4.8 14.3 1,200 2,499 5.1 9.7 600 1,199 4.0 5.8 Less than 600 20.6 4.8 *Totals may not equal 100.0 due to rounding. 3

Table 5: Percentage of Catholic School and Private (Non-Catholic) School Students by Geographic Region, Grades 1 12 Iowa Assessments Form E Fall 2017 National Comparison Study Catholic Geographic Region Percentage in Weighted Sample Percentage in Population* Northeast 24.8 28.1 Midwest 24.9 33.0 South 24.3 22.5 West 26.0 16.3 *Totals may not equal 100.0 due to rounding. Private (Non-Catholic) Geographic Region Percentage in Weighted Sample Percentage in Population* Northeast 23.5 20.0 Midwest 21.8 16.9 South 24.6 41.3 West 30.8 21.8 *Totals may not equal 100.0 due to rounding. 4

Participation of Students in Groups of Interest The records of students used to develop the 2017 norms for the Iowa Assessments included students with disabilities, English language learners, students from a variety of socio-economic and racial/ethnic groups. Although these groups were not a formal part of the stratification design, their representation in the data used to develop 2017 norms is of interest. Such characteristics of the sample are summarized in Table 6. In general, the differences between population and sample percentages are small. They are partly attributed to the fact that the population values are for public school students only, whereas about 10% of the students in the weighted sample are from Catholic and other private schools. As part of the standard administrative conditions for the Iowa Assessments, schools are given detailed instructions on testing students with disabilities and English Language Learners consistent with the conditions used in the national standardization program. Schools identify all students so classified, decide whether they should participate in the assessment, and if so, whether modifications in testing procedures were needed. In both the national standardization and in the administrations used in to develop the 2017 norms, among students with disabilities nearly all are identified as eligible for special education services and have an Individualized Education Program (IEP), an Individualized Accommodation Plan (IAP), or a Section 504 Plan. Schools examine the IEP or other plan for these students, decide whether the student should receive accommodations, and determine the nature of those accommodations. These steps are part of the regular administrative procedures for the Iowa Assessments. For students whose native language is not English and who have been in an English-only classroom for a limited time, two decisions are made prior to administering the assessment. First, is English-language acquisition developed sufficiently to warrant participation, and second, should the assessment involve the use of any particular accommodations? In all instances, the guidelines in place in the school district are implemented in making decisions about each student, and these decisions are part of the standard administrative conditions for the Iowa Assessments. Although not a direct part of a typical sampling plan, the ethnic and racial composition of a national sample should represent that of the school population. The racial-ethnic composition of the 2017 norming data was based on responses to demographic questions on answer documents. In all grades, students were asked to indicate their ethnicity as Hispanic or Non- Hispanic. A separate entry was provided in which students were told to indicate the racial group defined by the 2010 U.S. Census to which they belong. In kindergarten through grade 3, teachers furnished this information. In the remaining grades, students furnished it. Table 6 also summarizes racial-ethnic representation in the weighted kindergarten through grade 11 sample. The differences between the weighted sample and population percents are 5

generally small. They are partly attributed to the fact that the population values are for public school students only, whereas about 10% of the students in the weighted sample are from Catholic and other private schools. Note that the percents in the categories for race sum to the percent of students who indicated they were not Hispanic or Latino. Table 6: Participation of Students by Education Plan and Ethnicity/Race Iowa Assessments Form E, Grades 1 11 Fall 2017 National Comparison Study Education Plan Population Percent 1 Weighted Sample Percent 2 Individual Education Plan 13.0 5.4 504 Plan 1.2 0.7 English Language Learner 9.4 8.1 Free- and Reduced Price Lunch 48.1 31.4 Ethnicity Population Percent 1 Weighted Sample Percent 2 Hispanic or Latino 22.2 22.3 Not Hispanic or Latino 77.8 77.7 Race American Indian or Alaska Native 1.3 1.9 Asian 4.9 3.1 Black or African American 16.9 13.4 Native Hawaiian or Other Pacific Islander 0.1.6 White 54.6 58.7 1 Public schools only, NCES Common Core of Data, School Year 20015-16. 2 The weighted sample includes Catholic and other private schools. 6

Summary of the 2017 Norms Development Process The weighted sample yielded a set of frequency distributions for each test in each of the two-year periods (five two-year periods in all) over which the degree of change was estimated across all percentiles from one year to the next. Differences in matched pairs of consecutive years were summarized at the 10 th, 25 th, 50 th, 75 th and 90 th percentiles, and the average change for each pair of school years was aggregated across the five two-year periods. These differences were plotted and smoothed in order to establish the cumulative change in performance observed since the 2011 national standardization. The 2017 norms derived from this procedure minimize any undue influence of a particular user or group of users in two important ways. First, the weighted frequency distributions of raw scores were not themselves used to define updated norms, as is typically done to derive user norms. They were only used to estimate the amount of change observed across the score distributions. This approach is preferable, assuming no interaction exists between the characteristics that distinguish users of the tests from nonusers. Second, it preserves the essential characteristics and representativeness of the original national probability sample. Comparisons of 2011 and 2017 National Norms Table 7 compares the percentile ranks from the 2017 national norms with those from the 2011 national norms for reading, math, science, social studies, and language. Only selected percentiles (10, 25, 50, 75 and 90) are shown in each table as a means of describing the general trend of score changes due to changes in national performance. The left column shows the selected percentiles for the given base year (2011). The remaining columns show the associated percentile ranks for the 2017 norms. To determine how a grade 3 student who was at the 90th percentile on the reading test using the 2011 norms would have scored using the 2017 norms, go to the row labeled 90 and then read across to find the corresponding PR in grade 3. In this example, a student who scored at the 90th percentile on the reading test based on the 2011 norms would have received an NPR of 91 using the 2017 norms. As another example, a student in grade 3 who received an NPR of 50 on the mathematics test with the 2011 norms would have received an NPR of 58 using the 2017 norms. A comparison of the 2011 to 2017 national norms can be used to make the following general observations for grades 3 to 8: In general, the differences between the 2017 norms and the 2011 norms are small. The 2017 norms are most often somewhat easier than the 2011 norms, meaning that for a given level of performance based on 2011 norms, students are likely to receive slightly higher NPRs based on 2017 norms. This trend indicates that when systematic changes were observed between 2011 and 2017, student performance tended to go down. When the 2017 value is higher than the 2011 value, the newer norms are sometimes said to be easier. In reading, the average student (NPR = 50) in 2011 outperformed the average student in 2017 in grades 3 to 8. This is true for the other achievement levels as well. 7

In math, students at all achievement levels (low, average, and high) in 2011 in grades 3 to 8 outperformed students in 2017. In science, student performance in 2011 and 2017 was very similar. In social studies and language, students in 2011 outperformed students in 2017 in grades 3 to 8. For grades 9 to 11, performance of all students in 2017 was generally comparable to that of students in 2011. In addition, there were no significant differences in student performance in kindergarten through grade 2 in any subject area. Figures 1 to 30 illustrate the impact of the changes in performance across the entire distribution in the years since 2011 in five subject area for grades 3 through 8. Notice that the red line indicating the 2017 norms is generally to the left of the 2011 norms, consistent with the norms getting easier. Larger differences are generally seen in the middle elementary grades and at the lower end of the standard score distribution. To find the percentile rank for the alternate set of norms, find where the student s standard score on the horizontal axis intersects with the desired norm curve and read the NPR from the vertical axis. 8

Table 7: Comparison of the 2011 and 2017 National Norms, Grades 1 11 Corresponding 2017 NPRs Achievement Grade Level in 2011 1 2 3 4 5 6 7 8 9 10 11 90 90 90 91 91 91 91 91 91 90 90 90 75 75 75 78 77 77 77 77 77 75 75 75 50 50 50 54 53 53 53 52 52 50 50 50 25 25 25 28 27 27 26 27 27 25 25 25 10 10 10 12 12 11 12 11 11 10 10 10 Math Achievement Grade Level in 2011 1 2 3 4 5 6 7 8 9 10 11 90 90 90 93 92 92 92 92 92 90 90 90 75 75 75 80 79 78 78 78 78 75 75 75 50 50 50 58 55 54 54 54 53 50 50 50 25 25 25 29 30 29 28 28 28 25 25 25 10 10 10 14 13 13 12 12 12 10 10 10 Achievement Grade Level in 2011 1 2 3 4 5 6 7 8 9 10 11 90 90 90 90 90 91 90 90 90 90 90 90 75 75 75 76 76 76 76 76 76 75 75 75 50 50 50 52 51 51 51 52 51 50 50 50 25 25 25 28 26 27 26 26 26 25 25 25 10 10 10 11 11 11 10 11 10 10 10 10 Social Studies Grade Achievement Level in 2011 1 2 3 4 5 6 7 8 9 10 11 90 90 90 92 92 91 91 91 91 90 90 90 75 75 75 78 78 77 77 77 76 75 75 75 50 50 50 54 53 53 52 52 52 50 50 50 25 25 25 28 27 27 27 27 26 25 25 25 10 10 10 12 12 11 11 11 11 10 10 10 Language Grade Achievement Level in 2011 1 2 3 4 5 6 7 8 9 10 11 90 90 90 92 92 91 91 91 91 90 90 90 75 75 75 78 77 77 76 77 77 75 75 75 50 50 50 56 55 53 52 52 52 50 50 50 25 25 25 29 29 28 28 27 27 25 25 25 10 10 10 14 12 11 11 11 11 10 10 10 9

Figure 1 100 Grade 3-90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 National Standard Score 2011 Norms 2017 Norms Figure 2 100 Grade 4-90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 240 260 National Standard Score 2011 Norms 2017 Norms 10

Figure 3 100 Grade 5-90 80 70 NPR Scale 60 50 40 30 20 10 0 180 200 220 240 260 280 National Standard Score 2011 Norms 2017 Norms 100 Figure 4 Grade 6-90 80 70 NPR Scale 60 50 40 30 20 10 0 175 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 11

100 Figure 5 Grade 7-90 80 70 NPR Scale 60 50 40 30 20 10 0 175 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 100 Figure 6 Grade 8-90 80 70 NPR Scale 60 50 40 30 20 10 0 200 225 250 275 300 325 National Standard Score 2011 Norms 2017 Norms 12

100 Figure 7 Grade 3 - Math 90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 National Standard Score 2011 Norms 2017 Norms 100 Figure 8 Grade 4 - Math 90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 240 National Standard Score 2011 Norms 2017 Norms 13

100 Figure 9 Grade 5 - Math 90 80 70 NPR Scale 60 50 40 30 20 10 0 180 200 220 240 260 National Standard Score 2011 Norms 2017 Norms 100 Figure 10 Grade 6 - Math 90 80 70 NPR Scale 60 50 40 30 20 10 0 180 200 220 240 260 280 National Standard Score 2011 Norms 2017 Norms 14

100 Figure 11 Grade 7 - Math 90 80 70 NPR Scale 60 50 40 30 20 10 0 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 100 Figure 12 Grade 8 - Math 90 80 70 NPR Scale 60 50 40 30 20 10 0 200 225 250 275 300 325 National Standard Score 2011 Norms 2017 Norms 15

100 Figure 13 Grade 3-90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 National Standard Score 2011 Norms 2017 Norms 100 Figure 14 Grade 4-90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 240 260 National Standard Score 2011 Norms 2017 Norms 16

100 Figure 15 Grade 5-90 80 70 NPR Scale 60 50 40 30 20 10 0 180 200 220 240 260 280 National Standard Score 2011 Norms 2017 Norms 100 Figure 16 Grade 6-90 80 70 NPR Scale 60 50 40 30 20 10 0 175 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 17

100 Figure 17 Grade 7-90 80 70 NPR Scale 60 50 40 30 20 10 0 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 100 Figure 18 Grade 8-90 80 70 NPR Scale 60 50 40 30 20 10 0 200 250 300 National Standard Score 2011 Norms 2017 Norms 18

100 Figure 19 Grade 3 - Social Studies 90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 National Standard Score 2011 Norms 2017 Norms 100 Figure 20 Grade 4 - Social Studies 90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 240 National Standard Score 2011 Norms 2017 Norms 19

100 Figure 21 Grade 5 - Social Studies 90 80 70 NPR Scale 60 50 40 30 20 10 0 180 200 220 240 260 National Standard Score 2011 Norms 2017 Norms 100 Figure 22 Grade 6 - Social Studies 90 80 70 NPR Scale 60 50 40 30 20 10 0 175 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 20

100 Figure 23 Grade 7 - Social Studies 90 80 70 NPR Scale 60 50 40 30 20 10 0 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 100 Figure 24 Grade 8 - Social Studies 90 80 70 NPR Scale 60 50 40 30 20 10 0 200 250 300 National Standard Score 2011 Norms 2017 Norms 21

100 Figure 25 Grade 3 - Language 90 80 70 NPR Scale 60 50 40 30 20 10 0 160 180 200 220 240 National Standard Score 2011 Norms 2017 Norms 100 Figure 26 Grade 4 - Language 90 80 70 NPR Scale 60 50 40 30 20 10 0 150 175 200 225 250 275 National Standard Score 2011 Norms 2017 Norms 22

100 Figure 27 Grade 5 - Language 90 80 70 NPR Scale 60 50 40 30 20 10 0 175 200 225 250 275 300 National Standard Score 2011 Norms 2017 Norms 100 Figure 28 Grade 6 - Language 90 80 70 NPR Scale 60 50 40 30 20 10 0 200 250 300 National Standard Score 2011 Norms 2017 Norms 23

100 Figure 29 Grade 7 - Language 90 80 70 NPR Scale 60 50 40 30 20 10 0 200 250 300 National Standard Score 2011 Norms 2017 Norms 100 Figure 30 Grade 8 - Language 90 80 70 NPR Scale 60 50 40 30 20 10 0 200 250 300 350 National Standard Score 2011 Norms 2017 Norms 24

Methods of Determining and Reporting Reliability A soundly planned, carefully constructed and comprehensive large-scale assessment represents the most accurate and dependable measure of student achievement available to parents, teachers, and school officials. Many subtle, extraneous factors that contribute to unreliability and bias in human judgments have little or no effect on scores from carefully developed assessments. In addition, other factors that contribute to apparent inconsistency in student performance can be effectively minimized in the assessment situation: temporary changes in student motivation, health, and attentiveness; minor distractions inside and outside the classroom; limitations in number, scope, and comparability of the available samples of student work; and misunderstanding by students of what the teacher expects of them. The greater effectiveness of a well-constructed achievement test in controlling these factors compared to informal evaluations of the same achievement is evidenced by the higher reliability of the test. Test reliability can be quantified by a variety of statistical data, but such data reduce to two basic types of indices. The first of these indices is the reliability coefficient. In numerical value, the reliability coefficient is between.00 and.99; for standardized assessments it is generally between.60 and.95. The closer the coefficient approaches the upper limit, the greater the freedom of the scores from the influence of factors that temporarily affect student performance and obscure real differences in achievement. This ready frame of reference for reliability coefficients is deceptive in its simplicity, however. It is impossible to conclude whether a value such as.75 represents a high or low, satisfactory or unsatisfactory reliability. Only after a coefficient has been compared to those of equally valid and equally practical alternative assessments can such a judgment be made. In practice, there is always a degree of uncertainty regarding the terms equally valid and equally practical, so the reliability coefficient is rarely free of ambiguity. Nonetheless, comparisons of reliability coefficients for alternative approaches to assessment can be useful in determining the relative stability of the resulting scores. The second of the statistical indices used to describe test reliability is the standard error of measurement. This index represents a measure of the net effect of all factors leading to inconsistency in student performance and to inconsistency in the interpretation of that performance. The SEM can be understood by a hypothetical example. Suppose a group of students at the same achievement level in reading were to take the same reading test on two occasions. Despite their equal reading ability, they would not all get the same score both times. Instead, their scores would range across an interval. A very few would get much higher scores than expected given their achievement level and a few much lower; the majority would get scores quite close to their actual achievement level. Such variation in scores would be attributable to differences in motivation, attentiveness, and other situational factors. The SEM is an index of the typical range or variability of the scores observed for students regardless of their level of achievement. It tells the degree of precision in placing a student at a point on the score scale used for reporting assessment results. There is, of course, no way to know just how much a given student s achievement may have been under- or over-estimated from a single administration of a test. We may, however, make reasonable estimates of the amount by which the achievement of students in a particular 25

reference group has been mis-measured. For about two-thirds of the examinees, the scores obtained are correct or accurate to within one SEM of the observed score. For 95 percent of the students, the scores are accurate to within two standard errors, and for more than 99 percent, the scores are accurate to within three standard error values. Reliability estimates were obtained using Kuder-Richardson Formula 20 (K-R20). Reliability coefficients derived by this technique were based on national data and are reported for both fall and spring administrations. The coefficients for Form F of the Iowa Assessments Complete Battery are reported in this document in Table 8. Table 8 also reports fall and spring means and standard deviations (SDs) on the raw-score (RS) and national standard score (SS) scales. The SEM measures the net effect of all factors leading to inconsistency in student test scores and to inconsistency in score interpretation. It is reported as the typical amount by which a student s observed score may range from one testing occasion to another. In addition to the K-R 20 and SEM values, descriptive statistics are reported for fall and spring test administration in Table 8. 26

Table 8: Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 5 Grade K Language ELA Total Word Analysis Listening Extended ELA Core with ET and MT Extended Core with XET and MT R L V ET WA Li XET M CT XCT Number of Items 17 27 23 29 23 27 Fall Mean 6.8 19.1 17.6 19.2 13.7 17.2 RS SD 3.7 4.6 2.8 5.1 3.7 4.4 SEM 1.8 2.2 1.8 2.2 2.2 2.3 27 Mean 122.9 123.3 121.7 123.3 121.4 122.7 122.0 121.4 121.8 121.8 SS SD 8.8 8.6 13.1 8.6 12.9 9.3 8.9 8.9 9.0 9.0 SEM 4.2 4.0 7.6 2.8 5.6 5.5 2.3 4.6 2.7 2.6 Reliability.764.775.659.894.809.647.934.724.909.917 Spring K Mean 10.8 22.4 19.2 22.5 16.5 21.4 RS SD 3.7 3.3 2.1 3.7 3.6 4.1 SEM 1.8 1.8 1.4 1.9 1.9 1.9 Mean 131.3 130.4 131.1 130.8 131.5 130.8 130.9 130.7 130.8 130.8 SS SD 7.4 8.5 10.1 8.5 14.3 10.8 11.1 9.8 9.8 9.8 SEM 3.5 4.6 6.8 3.2 7.6 5.9 2.5 4.6 2.8 2.6 Reliability.769.701.544.855.717.696.941.773.916.924

Table 8: Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 6 Language ELA Total Word Analysis Listening Extended ELA Core with ET and MT Extended Core with XET and MT R L V ET WA Li XET M CT XCT Number of Items 34 31 27 33 27 35 Fall Grade 1 Mean 19.5 25.1 21.5 27.2 18.1 26.1 RS SD 7.2 2.8 2.7 4.5 4.0 5.7 SEM 2.5 1.3 1.6 1.9 2.1 2.2 28 Mean 139.1 137.3 138.1 138.0 138.9 138.1 138.2 138.3 138.2 138.3 SS SD 10.2 9.6 16.0 9.9 15.9 11.9 12.3 11.3 10.9 10.9 SEM 3.5 4.6 9.7 3.8 6.6 6.3 3.0 4.3 2.9 2.6 Reliability.881.769.632.849.826.720.941.856.930.943 Spring Grade K Mean 13.5 23.0 20.3 25.0 15.6 22.2 RS SD 5.7 3.0 2.8 5.2 4.1 5.7 SEM 2.6 1.3 1.8 2.1 2.2 2.5 Mean 131.3 130.4 131.1 130.8 131.5 130.8 130.9 130.7 130.8 130.8 SS SD 7.4 8.5 15.0 8.5 14.3 10.8 11.1 9.8 9.8 9.8 SEM 3.3 3.8 9.8 3.7 5.9 5.9 2.8 4.3 2.8 2.6 Reliability.799.799.574.809.830.703.935.812.917.932

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 7 Language ELA Total Word Analysis Listening Extended ELA Computation Math Total Core Composite Extended English Language Arts Total Core Composite with ET and M Core Composite with XET and M Social Studies Complete Composite Complete Composite with XET and MT Complete Composite with ET and M Complete Composite with XET and M R L V ET WA Li XET M MC MT CT XET CT- XCT- SC SS CC XCC CC- XCC- Number of Items 35 34 26 32 27 41 25 29 29 Fall Grade 2 Mean 24.0 22.2 19.8 25.5 21.2 31.0 19.2 24.0 23.3 RS SD 7.3 6.9 4.8 4.4 3.5 5.8 4.6 3.2 3.4 SEM 2.3 2.3 1.8 2.0 1.8 2.3 1.9 1.8 1.8 29 Mean 158.9 158.1 157.5 158.3 159.2 156.9 158.2 157.0 154.2 156.1 157.2 157.1 157.6 157.6 157.4 157.8 157.3 157.3 157.6 157.6 SS SD 16.3 15.1 19.0 15.1 20.4 14.8 14.0 14.8 9.9 12.8 13.4 13.4 13.8 13.8 18.3 16.3 13.0 13.0 13.2 13.2 SEM 5.2 5.0 7.1 3.2 9.1 7.7 2.9 5.9 4.0 4.1 2.6 2.5 3.4 3.3 10.5 8.9 2.9 2.9 3.2 3.2 Reliability.900.891.861.954.802.728.956.842.836.895.961.964.941.943.669.704.951.952.941.942 Spring Grade 1 Mean 20.9 18.4 18.0 24.0 19.6 28.3 17.4 22.7 22.0 RS SD 7.6 5.8 5.0 4.5 3.7 5.8 4.8 3.5 3.7 SEM 2.5 2.5 2.0 2.2 2.0 2.6 2.1 2.0 2.0 Mean 152.2 149.9 150.9 150.8 152.2 150.4 151.0 150.3 150.1 150.2 150.5 150.6 150.6 150.6 149.8 151.1 150.5 150.6 150.5 150.6 SS SD 14.3 11.3 18.0 11.3 18.4 13.5 12.6 13.6 9.3 11.2 12.2 12.2 12.7 12.7 16.8 15.2 11.8 11.8 12.3 12.3 SEM 4.6 5.0 7.2 3.1 8.8 7.3 2.8 6.0 4.0 4.2 2.6 2.5 3.4 3.3 9.7 8.3 2.8 2.7 3.1 3.1 Reliability.897.811.842.923.772.708.950.803.818.857.953.956.928.931.669.700.945.947.936.938

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 8 Language ELA Total Word Analysis Listening Extended ELA Computation Math Total Core Composite Extended English Language Arts Total Core Composite with ET and M Core Composite with XET and M Social Studies Complete Composite Complete Composite with XET and MT Complete Composite with ET and M Complete Composite with XET and M R L V ET WA Li XET M MC MT CT XET CT- XCT- SC SS CC XCC CC- XCC- Number of Items 38 42 26 33 27 46 27 29 29 Fall Grade 3 Mean 31.1 32.8 20.8 28.0 23.4 33.6 19.9 21.9 21.7 RS SD 6.3 7.4 4.3 4.3 2.9 7.5 3.6 4.0 3.3 SEM 2.0 2.2 1.7 1.8 1.5 2.5 2.0 2.0 1.9 30 Mean 177.5 177.0 175.4 176.9 177.6 174.6 176.6 175.3 172.3 174.3 175.6 175.5 176.1 176.0 177.0 176.6 176.0 175.9 176.3 176.2 SS SD 21.4 19.5 20.6 20.1 25.4 17.3 17.1 18.4 13.9 16.0 16.7 16.7 17.4 17.4 22.5 19.4 17.1 17.1 17.1 17.1 SEM 6.9 5.8 8.0 3.9 10.8 9.0 3.5 6.2 8.0 4.9 3.1 3.0 3.7 3.5 11.5 11.0 3.4 3.3 3.6 3.5 Reliability.896.911.848.961.820.728.958.888.671.907.965.967.956.958.741.681.961.962.956.957 Spring Grade 2 Mean 29.2 30.8 19.5 27.0 22.4 30.8 18.9 20.5 20.6 RS SD 6.8 7.1 4.5 4.5 3.3 7.5 3.7 4.2 3.2 SEM 2.3 2.5 1.9 2.0 1.7 2.7 2.1 2.2 2.0 Mean 170.7 169.8 168.6 169.9 171.0 168.2 169.8 168.6 168.3 168.5 169.2 169.1 169.2 169.2 169.7 169.5 169.3 169.3 169.4 169.3 SS SD 19.6 17.2 19.8 17.2 23.7 16.3 16.1 16.9 13.1 14.7 15.3 15.3 15.9 15.9 21.2 17.8 15.0 15.0 15.2 15.2 SEM 6.5 6.1 8.2 4.0 10.3 8.5 3.5 6.1 7.6 4.8 3.1 3.0 3.7 3.5 11.1 11.1 3.3 3.3 3.6 3.5 Reliability.890.875.827.947.812.728.954.868.660.892.958.962.947.951.724.610.950.952.944.946

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Conventions of Writing Level 9 Grade 3 Written Expression Spelling Capitalization Punctuation Conventions of Writing Total ELA Total Word Analysis Listening Extended ELA R WE SP CP PC CW V ET WA Li XET Number of Items 41 35 24 20 20 29 33 28 Fall Mean 23.1 18.5 12.4 9.5 8.6 15.1 21.0 16.2 RS SD 8.6 8.0 5.1 4.7 4.0 6.5 5.2 3.7 SEM 2.8 2.6 2.1 2.0 1.9 2.4 2.5 2.3 31 Mean 177.5 176.8 175.4 175.1 177.5 174.2 175.4 176.3 177.6 174.6 176.2 SS SD 21.4 23.9 17.9 23.2 23.6 19.5 20.6 20.1 25.4 17.3 17.1 SEM 7.0 7.7 7.3 9.6 11.3 5.5 7.5 3.8 12.2 10.8 3.7 Reliability.894.895.834.828.772.920.867.964.771.613.953 Spring Mean 26.7 21.9 15.1 11.7 10.3 18.0 22.8 18.1 RS SD 8.4 8.3 5.2 5.1 4.4 6.7 5.4 3.8 SEM 2.7 2.5 2.0 1.9 1.9 2.3 2.4 2.2 Mean 187.8 188.7 185.8 187.2 188.3 185.2 185.0 187.2 187.2 184.2 186.7 SS SD 24.5 28.2 20.4 29.2 27.4 22.7 21.6 21.7 28.6 19.2 19.0 SEM 7.7 8.4 7.8 10.7 11.9 5.9 7.4 4.1 12.7 10.8 3.9 Reliability.901.911.854.866.812.932.883.964.804.683.958

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 9 Grade 3 Computation Math Total Core Composite Core Composite with XET Core Composite with ET and M Core Composite with XET and M Social Studies Complete Composite Complete Composite with XET and MT Complete Composite with ET and M Complete Composite with XET and M M MC MT CT XCT CT- XCT- SC SS CC XCC CC- XCC- Number of Items 50 25 30 30 Fall Mean 27.6 12.3 14.0 17.3 32 RS SD 8.3 5.8 6.3 6.6 SEM 3.1 2.1 2.4 2.4 Mean 175.3 172.3 174.3 175.3 175.3 175.8 175.8 177.0 176.6 175.8 175.8 176.1 176.1 SS SD 18.4 13.9 16.0 16.7 16.7 17.4 17.4 22.5 19.4 17.1 17.1 17.1 17.1 SEM 6.9 5.1 4.3 2.9 2.8 4.0 3.9 8.4 7.0 2.6 2.6 3.2 3.2 Reliability.858.868.928.971.971.948.949.861.870.976.976.965.965 Spring Mean 32.2 17.0 16.6 20.3 RS SD 8.8 6.0 6.6 6.4 SEM 3.0 1.9 2.3 2.2 Mean 185.9 185.4 185.7 186.4 186.2 186.5 186.3 187.4 186.8 186.7 186.5 186.7 186.6 SS SD 20.5 16.7 17.7 19.1 19.1 19.9 19.9 25.2 21.7 19.9 19.9 20.0 20.0 SEM 6.9 5.2 4.3 3.0 2.9 4.0 4.0 8.8 7.6 2.8 2.7 3.3 3.3 Reliability.886.902.940.975.977.959.960.878.877.980.981.972.973

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 10 Grade 4 Written Expression Spelling Conventions of Writing Capitalization Punctuation Conventions of Writing Total ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE SP CP PC CW V ET M MC MT CT CT- SC SS CC CC- Number of Items 42 38 27 22 22 34 55 27 34 34 Fall Mean 23.8 20.6 15.4 11.2 9.4 19.7 31.6 15.7 16.7 19.2 RS SD 8.7 8.6 5.7 4.7 4.6 7.7 9.3 6.2 6.7 6.9 SEM 2.8 2.7 2.2 2.0 2.0 2.5 3.2 2.2 2.6 2.5 33 Mean 193.8 195.1 192.2 194.0 195.4 191.9 191.1 193.5 191.8 188.8 190.8 192.1 192.6 193.8 192.6 192.5 192.8 SS SD 25.9 30.5 22.2 31.4 30.0 24.9 22.5 22.8 21.8 17.4 18.9 20.4 21.2 26.6 23.3 21.4 21.3 SEM 8.4 9.6 8.6 13.5 13.0 6.9 7.3 4.6 7.6 6.2 5.4 3.5 4.4 10.1 8.5 3.2 3.7 Reliability.895.902.850.814.811.923.895.960.880.875.917.970.957.857.866.977.970 Spring Mean 26.2 23.0 17.5 12.5 10.7 22.5 35.5 19.3 19.1 21.9 RS SD 8.6 8.8 5.7 4.9 5.2 7.4 9.5 6.1 7.1 7.1 SEM 2.7 2.6 2.1 1.9 2.0 2.4 3.1 2.0 2.5 2.4 Mean 202.6 204.9 202.5 204.0 204.9 201.8 199.9 202.8 201.6 200.7 201.3 202.0 202.2 203.5 202.6 202.4 202.5 SS SD 28.7 34.6 25.3 36.2 34.4 28.4 23.4 24.4 24.0 20.5 21.1 22.9 23.7 29.2 26.4 23.9 23.9 SEM 9.1 10.2 9.4 14.3 13.1 7.2 7.6 4.9 7.9 6.6 6.7 3.7 4.6 10.4 9.0 3.4 3.8 Reliability.900.914.861.844.854.936.895.960.893.896.928.973.962.874.884.980.974

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 11 Grade 5 Written Expression Spelling Conventions of Writing Capitalization Punctuation Conventions of Writing Total ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE SP CP PC CW V ET M MC MT CT CT- SC SS CC CC- Number of Items 43 40 30 24 24 37 60 29 37 37 34 Fall Mean 24.3 23.0 17.7 11.9 10.4 21.8 34.3 18.8 19.9 21.0 RS SD 9.0 9.3 6.3 5.1 5.3 7.9 10.1 6.4 7.6 8.3 SEM 2.9 2.7 2.3 2.1 2.1 2.5 3.3 2.3 2.7 2.6 Mean 207.0 209.8 207.7 209.0 210.3 206.9 205.1 207.6 206.7 204.2 205.9 206.8 207.2 208.5 207.2 207.1 207.4 SS SD 29.9 36.4 26.8 37.9 36.6 30.5 24.0 25.4 25.6 21.4 22.3 24.2 25.4 30.6 28.2 25.2 25.1 SEM 9.6 10.6 10.0 15.5 14.7 7.9 7.7 5.1 8.5 7.5 6.2 4.0 4.9 10.8 8.9 3.5 4.0 Reliability.897.916.861.833.838.934.897.960.891.877.924.973.962.876.900.980.974 Spring Mean 26.7 25.1 19.7 13.2 11.6 24.6 37.4 21.4 22.0 23.5 RS SD 9.0 9.5 6.3 5.3 5.7 8.1 10.5 6.1 7.9 8.5 SEM 2.8 2.6 2.3 2.1 2.1 2.4 3.2 2.1 2.6 2.5 Mean 215.5 218.9 216.9 218.5 219.3 216.1 214.0 216.5 215.8 215.3 215.6 216.0 216.1 217.9 217.0 216.5 216.6 SS SD 32.2 40.1 29.3 41.0 40.0 33.3 25.5 27.3 27.9 24.7 24.8 26.3 27.2 33.3 31.2 27.5 27.7 SEM 10.0 11.0 14.5 15.8 14.5 8.0 7.5 5.3 8.6 8.3 6.3 4.1 5.0 11.0 9.3 3.6 4.1 Reliability.904.925.871.851.868.943.913.963.906.886.935.975.966.891.912.982.978

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 12 Grade 6 Written Expression Spelling Conventions of Writing Capitalization Punctuation Conventions of Writing Total ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE SP CP PC CW V ET M MC MT CT CT- SC SS CC CC- Number of Items 44 43 32 25 25 39 65 30 39 39 35 Fall Mean 26.2 25.7 17.9 13.2 12.4 24.3 35.6 19.1 21.8 22.8 RS SD 8.9 9.0 7.0 4.6 5.3 7.6 11.5 6.1 7.6 7.9 SEM 2.9 2.8 2.4 2.2 2.2 2.6 3.5 2.3 2.7 2.8 Mean 220.0 223.3 221.5 223.1 224.0 220.6 219.2 221.0 220.5 219.3 220.1 220.6 220.8 221.8 221.5 221.0 221.1 SS SD 33.4 41.7 30.3 42.1 41.5 34.8 26.3 28.2 28.9 25.7 25.8 27.5 28.2 34.6 32.5 28.5 28.5 SEM 10.8 13.0 10.3 20.3 16.9 9.4 9.0 6.0 8.8 9.4 6.7 4.5 5.3 12.5 12.0 4.2 4.6 Reliability.895.903.885.768.835.927.882.954.908.856.933.973.964.869.879.979.974 Spring Mean 28.0 27.1 19.4 13.9 13.4 26.2 38.6 20.8 23.7 24.6 RS SD 8.8 9.4 7.0 4.8 5.7 7.6 11.7 6.3 7.7 8.1 SEM 2.8 2.7 2.4 2.2 2.1 2.5 3.4 2.2 2.7 2.7 Mean 227.3 230.8 229.5 231.1 232.4 228.7 226.7 228.6 228.7 228.4 228.6 228.6 228.7 230.7 229.6 229.1 229.2 SS SD 35.3 45.0 32.2 44.6 45.4 36.8 27.5 29.6 30.6 29.3 27.9 28.9 29.8 36.8 35.5 30.4 30.5 SEM 12.2 14.23 11.5 21.9 18.2 10.2 9.0 6.7 9.9 11.5 7.6 5.1 6.0 13.8 12.8 4.6 5.1 Reliability.900.915.885.793.863.934.890.957.915.882.939.975.967.880.893.981.977

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 13 Grade 7 Written Expression Spelling Conventions of Writing Capitalization Punctuation Conventions of Writing Total ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE SP CP PC CW V ET M MC MT CT CT- SC SS CC CC- Number of Items 45 45 34 27 27 41 70 31 41 41 36 Fall Mean 25.6 24.3 17.9 14.1 10.8 23.7 35.5 17.1 21.7 22.1 RS SD 9.1 9.5 7.3 4.7 5.6 7.6 13.5 6.7 8.3 8.0 SEM 2.9 2.9 2.5 2.3 2.2 2.7 3.6 2.4 2.8 2.8 Mean 231.3 234.7 233.5 235.4 236.8 232.9 231.2 232.7 232.8 231.8 232.5 232.6 232.8 233.9 233.2 232.9 233.0 SS SD 36.3 46.3 32.8 45.9 47.0 38.2 28.2 30.4 31.7 30.1 28.5 29.9 30.8 37.8 36.4 31.4 31.8 SEM 11.7 14.1 11.3 22.2 18.4 10.3 10.1 6.6 8.5 10.9 6.7 4.7 5.4 12.7 12.9 4.3 4.6 Reliability.896.907.882.767.847.927.871.953.928.869.944.975.970.888.875.981.979 Spring Mean 27.2 25.6 19.6 14.9 11.7 25.5 38.3 18.8 23.5 23.7 RS SD 9.3 9.9 7.3 4.9 6.0 7.6 14.2 7.2 8.6 8.3 SEM 2.9 2.9 2.5 2.3 2.2 2.7 3.6 2.3 2.7 2.8 Mean 238.4 241.6 240.9 242.5 243.6 239.9 238.1 239.7 240.4 240.6 240.5 240.1 240.0 241.7 240.7 240.4 240.4 SS SD 38.6 48.8 34.0 48.1 49.2 40.0 29.0 32.1 33.9 33.5 30.9 31.8 32.9 39.9 39.0 33.2 33.6 SEM 11.8 14.1 11.5 22.2 18.1 10.3 10.3 6.6 8.5 11.0 6.7 4.7 5.4 12.7 13.1 4.4 4.7 Reliability.906.916.886.787.865.934.873.958.937.893.952.978.973.899.888.983.980

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 14 Grade 8 Written Expression Spelling Conventions of Writing Capitalization Punctuation Conventions of Writing Total ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE SP CP PC CW V ET M MC MT CT CT- SC SS CC CC- Number of Items 46 48 35 29 29 42 75 32 43 43 37 Fall Mean 26.6 26.1 18.8 14.8 14.1 23.4 37.8 18.1 21.5 22.3 RS SD 9.4 10.1 7.6 5.5 6.5 9.6 14.1 7.1 7.8 8.7 SEM 3.0 3.1 2.5 2.3 2.3 2.6 3.8 2.5 2.9 2.9 Mean 242.3 245.2 244.4 246.0 247.2 243.4 241.9 243.4 244.2 243.9 244.1 243.8 243.8 245.0 244.2 244.0 244.1 SS SD 39.5 50.2 34.5 49.0 50.0 41.0 29.7 32.8 34.5 34.1 31.6 32.6 33.5 40.6 39.8 33.9 34.4 SEM 12.4 15.4 11.5 20.5 17.6 9.8 8.2 6.9 9.3 11.9 7.4 5.1 5.8 15.0 13.1 4.7 5.1 Reliability.901.906.889.825.876.943.924.955.927.878.946.976.970.863.891.980.978 Spring Mean 28.0 27.2 20.0 15.3 14.7 25.5 40.4 19.5 22.8 23.5 RS SD 9.6 10.4 7.6 5.6 6.7 9.6 14.5 7.4 8.1 9.1 SEM 2.9 3.0 2.5 2.3 2.3 2.6 3.8 2.4 2.9 2.8 Mean 248.9 251.5 251.2 251.7 252.4 249.2 248.7 249.8 250.7 251.3 250.9 250.3 250.2 251.5 250.6 250.6 250.5 SS SD 41.4 52.6 35.6 50.5 51.6 42.6 30.9 34.1 36.1 36.8 33.2 33.6 34.5 42.4 42.1 35.2 35.6 SEM 12.6 15.2 11.1 20.5 17.7 9.8 8.4 6.9 9.4 11.8 7.4 5.1 5.8 15.0 13.2 4.7 5.1 Reliability.908.916.894.836.882.947.927.959.932.898.950.977.971.875.902.982.979

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 15 Grade 9 Written Expression ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE V ET M MC MT CT CT- SC SS CC CC- Number of Items 40 54 40 40 30 48 50 38 Fall Mean 20.0 25.8 18.9 16.6 12.4 20.5 19.2 RS SD 9.2 14.1 9.3 8.0 6.1 8.7 8.7 SEM 2.7 3.1 2.7 2.8 2.4 3.1 3.1 Mean 252.4 254.7 251.8 253.5 254.0 254.4 254.1 253.8 253.7 254.3 253.6 253.8 253.8 SS SD 42.4 43.0 31.4 34.7 36.6 37.5 33.8 34.0 34.8 42.6 42.7 35.5 36.0 SEM 12.7 9.4 8.9 6.5 12.7 14.6 9.7 5.9 7.1 15.3 15.5 5.3 6.0 Reliability.910.952.919.965.880.849.917.970.958.871.868.977.972 Spring Mean 21.3 27.5 20.8 17.7 13.3 21.8 20.9 RS SD 9.6 14.6 9.8 8.2 6.5 9.5 9.8 SEM 2.7 3.0 2.6 2.8 2.3 3.1 3.1 Mean 258.8 260.2 258.2 259.4 259.9 259.6 259.8 259.6 259.7 260.4 259.6 259.7 259.8 SS SD 44.4 43.3 32.7 35.8 38.0 39.0 34.9 34.5 35.6 43.5 43.7 36.5 36.8 SEM 12.6 9.0 8.7 6.3 12.9 14.0 9.8 5.8 7.2 14.3 14.0 5.1 5.8 Reliability.920.957.929.969.885.871.922.972.959.892.898.980.975

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 16 Grade 10 Written Expression ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE V ET M MC MT CT CT- SC SS CC CC- Number of Items 40 54 40 40 30 48 50 39 Fall Mean 19.9 26.1 19.7 16.4 12.2 21.2 20.4 RS SD 9.7 11.1 9.1 7.9 6.4 9.4 9.4 SEM 2.7 3.3 2.7 2.8 2.3 3.1 3.1 Mean 261.7 263.0 260.6 262.2 262.6 262.7 262.6 262.4 262.4 262.9 262.1 262.4 262.4 SS SD 44.9 44.0 33.0 36.0 38.5 39.3 35.4 35.1 36.0 44.0 44.2 36.9 37.0 SEM 12.4 13.1 9.8 7.9 13.5 14.2 10.2 6.4 7.8 14.5 14.7 5.5 6.2 Reliability.924.912.912.952.877.869.917.966.953.892.890.978.972 Spring Mean 21.0 27.2 21.1 17.4 12.9 22.2 21.4 RS SD 10.0 11.4 9.4 8.3 6.8 9.9 10.1 SEM 2.6 3.3 2.7 2.8 2.3 3.1 3.1 Mean 266.5 267.7 265.9 267.0 267.3 266.9 267.2 267.1 267.2 267.5 266.9 267.1 267.2 SS SD 46.2 45.1 34.1 36.8 39.5 40.5 36.5 36.0 36.6 45.3 45.5 37.7 37.6 SEM 12.3 12.9 9.6 7.8 13.1 13.7 9.9 6.3 7.7 14.1 14.1 5.4 6.1 Reliability.929.918.920.955.889.885.926.969.956.903.904.980.974

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 17/18 Grade 11 Written Expression ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M R WE V ET M MC MT CT CT- SC SS CC CC- Number of Items 40 54 40 40 30 48 50 40 Fall Mean 22.0 28.0 21.2 15.1 14.5 21.1 22.2 RS SD 10.1 12.0 8.6 8.4 7.2 9.2 10.1 SEM 2.6 3.2 2.8 2.7 2.3 3.1 3.1 Mean 268.8 269.9 268.1 269.2 269.7 269.5 269.6 269.4 269.5 269.7 269.1 269.4 269.4 SS SD 46.4 45.5 34.2 37.2 39.7 41.0 37.0 36.2 37.1 45.8 45.9 38.2 37.9 SEM 12.0 12.3 14.5 7.7 12.7 13.3 9.6 6.2 7.4 15.4 14.3 5.4 6.1 Reliability.933.927.899.957.897.894.933.971.960.887.903.980.974 Spring Mean 22.8 29.2 22.4 16.2 15.1 22.0 23.2 RS SD 10.2 12.3 8.9 9.1 7.4 9.6 10.5 SEM 2.6 3.2 2.7 2.7 2.3 3.1 3.1 Mean 273.0 274.3 272.6 273.6 273.9 273.3 273.7 273.6 273.7 273.8 273.3 273.6 273.7 SS SD 47.3 46.7 35.3 38.2 41.1 42.1 37.8 36.8 37.8 46.9 46.8 38.7 38.8 SEM 12.1 12.1 10.8 7.5 12.2 13.1 9.2 5.9 7.2 15.1 14.0 5.2 5.9 Reliability.935.933.907.962.912.903.940.974.964.897.911.982.977

Table 8 (continued): Means, Standard Deviations (SD), Reliability Coefficients (K-R 20), and Standard Errors of Measurement (SEM) for the Weighted Sample, Levels 5 17/18 Iowa Assessments Form F Level 17/18 Grade 12 Written Expression ELA Total Computation Math Total Core Composite Core Composite with ET and M Social Studies Complete Composite Complete Composite with ET and M 41 R WE V ET M MC MT CT CT- SC SS CC CC- Number of Items 40 54 40 40 30 48 50 Fall Mean 23.1 29.7 22.7 16.5 15.4 22.3 23.7 RS SD 10.2 12.4 9.0 9.3 7.5 9.7 10.7 SEM 2.6 3.2 2.7 2.7 2.3 3.1 3.1 Mean 274.6 276.1 273.9 275.2 275.6 275.1 275.4 275.3 275.4 274.9 275.1 275.2 275.3 SS SD 47.3 46.8 35.3 38.2 41.4 42.5 38.1 37.1 37.8 47.1 47.0 39.0 39.2 SEM 12.0 12.0 11.0 7.4 12.0 13.1 9.1 5.9 7.1 15.0 13.6 5.2 5.8 Reliability.936.934.910.962.916.905.943.975.965.899.916.982.978 Spring Mean 23.8 30.6 23.7 17.3 16.0 23.1 24.7 RS SD 10.3 12.6 9.1 9.7 7.7 10.0 11.2 SEM 2.6 3.1 2.7 2.7 2.3 3.1 3.1 Mean 278.2 279.6 277.6 278.8 278.8 278.7 278.8 278.8 278.8 278.3 279.1 278.8 278.8 SS SD 48.1 47.7 36.2 38.8 42.3 43.4 38.7 37.8 38.2 47.7 47.9 39.4 39.5 SEM 12.0 11.9 10.6 7.4 11.7 12.0 8.9 5.8 6.9 14.7 13.3 5.1 5.7 Reliability.938.938.915.964.924.912.947.977.967.905.923.983.979

Difficulty of the Assessments Teachers often remark that large-scale assessments, particularly when those assessments are used for accountability, are too difficult. To some extent, this perception is a reflection of the fact that items in well-designed large-scale assessments span a range of difficulty at any given grade level. No single assessment can be perfectly suited in difficulty for all students in a heterogeneous grade group. Individualized testing can be considered to help avoid extreme cases of an assessment not being well matched to the achievement level of certain students. In other situations, it is important to realize that an assessment aligned to important and often rigorous content standards, not to mention an assessment intended to provide information about the strengths and weaknesses of a large group of students, must include a range of difficulty in individual items. To obtain high reliability of scores observed within a group, an assessment must use nearly the entire range of possible scores; the raw scores on the test should range from near zero to the highest possible score so that the items provide information about the range of examinees for which the test is intended. The best way to ensure such a continuum is to conduct one or more preliminary tryouts of items that will determine objectively the difficulty and discriminating power of the items. A few items included in the final test should be so easy that at least 90 percent of students answer them correctly. These items allow the assessment to identify the least-able students. Similarly, a few very difficult items should be included to challenge the most-able students. The remainder of the items, however, should cover a broad range of medium difficulty and should discriminate well at all levels of ability. An assessment constructed in this manner results in the widest possible range of scores and yields the highest reliability per unit of testing time. The twelve levels of the Iowa Assessments were assembled to provide reliable and valid coverage of subject matter that spans the continuum of learning from kindergarten to grade 12. Item content classifications, cognitive level descriptors, and difficulty indices for three times of the school year (fall, midyear, and spring) are provided in the Content Classifications Guide, Levels 5/6 14 and Levels 15 17/18 for the Iowa Assessments Forms E, F, and G. A summary of the Form F difficulty and discrimination indices for all tests and grades is presented in Table 9. The difficulty indices reported for each grade are item proportions (pvalues) correct rather than percentage correct. These data were derived from the 2017 normative update; the mean item proportions correct are shown in bold; the 10 th, 50 th (median) and 90 th percentiles of the distributions are given as well. Appropriateness of test difficulty can best be ascertained by examining relationships between raw scores, standard scores, and percentile ranks in the tables in the Norms and Score Conversions. For example, the norms tables indicate that 38 of 40 items on Level 15 of the test must be answered correctly to score at the 99 th percentile in the fall of grade 9, and 40 items must be answered correctly to score at the 99 th percentile in the spring. Similarly, the number of items needed to score at the median in fall, midyear, and spring in grade 9 are 22, 23, and 24 out of 40 respectively. This test thus appears to be appropriate in item difficulty for the grade in which it is typically administered. 42

It should be noted that these difficulty characteristics are for a cross section of attendance centers in the nation. The distributions of item difficulty vary markedly among attendance centers, both within and between school systems. When the same levels of the assessments are administered to all students in a given grade in some schools, the tests are too difficult; in other schools they may be too easy. When tests are too difficult, students scores may be determined largely by chance. When tests are too easy and scores approach the maximum possible, a student s true achievement level may be seriously underestimated. Both content and difficulty should be considered when assigning specific levels of the assessment to individual students. The tasks reflected by the test questions and the content standards and domains covered should be relevant to the student s needs and level of development and should be in line with the purpose of the local assessment program. At the same time, the level of difficulty of the items should be such that the test is challenging, but success is attainable. As discussed previously, item discrimination indices (item-total correlations) are routinely examined during field testing and are one of several criteria used for item selection. Developmental discrimination (changes in an item s difficulty across grades) is inferred from field-test and standardization data that shows that items administered at adjacent grade levels have increasing p-values from grade to grade. A well-constructed assessment strives for items with strong correlations with total scores on the other items included in the test. Summary statistics from the distributions of item-total biserial correlations (item discrimination indices) are also reported in Table 9. The means (in bold) and the 10 th, 50 th, and 90 th percentiles of the distributions of biserial correlations are included. As would be expected, discrimination indices vary considerably from grade to grade, test to test, and even from one skill domain to another. In general, discrimination indices tend to be higher for tests that are relatively homogeneous in content and lower for tests that include complex stimuli or for skill domains within tests that require complex cognitive processes classified at higher cognitive levels. 43