What is a growth model?
For K-12 education, the phrase "growth model" describes a method of measuring individual student progress on statewide assessments (tests) by tracking the scores of the same students from one year to the next.
Traditional student assessment reports tell you about a student's achievement, whereas growth reports tell you how much change or "growth" there has been in achievement from year to year.
What questions can a growth model help answer?
The growth model allows districts and schools to more easily identify promising, or potentially struggling, programs and practices-and therefore to look deeper into what may or may not be working. A growth model can help answer such questions as:
- How much academic progress did an individual or group of students make in one or more years?
- How does an individual student's growth compare to that of students with similar prior MCAS test scores?
- Is a student's, school's or district's growth higher than, or lower than, or similar to typical1 growth?
- Which schools or districts demonstrate better than (or less than) typical growth for their students as compared to schools or districts with similar overall MCAS achievement?
Why did Massachusetts develop a growth model to measure student progress?
Annually, since 1998, Massachusetts has provided students, families, educators, and the general public with information about student, school and district performance based on the Massachusetts Comprehensive Assessment System (MCAS). This information has been invaluable in helping schools and districts engage in program evaluation activities-understanding, for example, how well district instruction and curriculum are aligned with the state's curriculum frameworks, or how well a particular subgroup of students is performing by school, district, and across the state.
Until now, however, we have been unable to answer the question, "How much academic progress did a student or group of students make in one year, as measured by MCAS, in relation to their academic peers?" With the development of the growth model, it is now possible to answer this question. This method of examining student performance and improvement will help districts and schools to look into why results differ for certain groups of students and support discovery of which approaches are working best to help more students to higher levels of academic performance.
How does Massachusetts measure student growth?
Massachusetts measures growth for an individual student by comparing the change in his or her MCAS achievement from one year to a subsequent year to that of all other students in the state who had similar historical MCAS results (the student's "academic peers"). This change in achievement is reported as a student growth percentile (abbreviated SGP) and indicates how high or low that student's growth was as compared to that of his/her academic peers (See Questions 15 and 16 for technical details).
For a school or district, the growth percentiles for all students are aggregated to create a median student growth percentile for the school or district. The median student growth percentile is a representation of "typical" growth for students in the school or district.
Why didn't Massachusetts report growth previously?
Massachusetts needed three things to be able to measure and report student growth:
- A statewide individual student tracking system (SIMS);
- Statewide assessments administered in consecutive grades in the same subjects (MCAS ELA and mathematics, grades 3-8);
- A technically sound and understandable method for measuring growth that was compatible with the MCAS system.
The state had all three of these components in place as of 2008.
When do growth reports become publicly available?
Massachusetts releases public growth reports for schools and districts along with the other MCAS achievement results in the fall of each school year. The state issues individual student growth reports to parents and guardians in the MCAS Parent Report shortly after the public release.
For which grades and subjects does Massachusetts report growth?
Massachusetts reports growth for ELA and mathematics for grades 4 through 8, and grade 10.
The Massachusetts growth model uses students' historical MCAS results to calculate growth percentiles.. As such, no results will be available for grade 3 (the first grade of MCAS testing) or for science (because science is tested only in grades 5, 8, and high school).
- While there is no 9th grade testing in ELA or mathematics, the Department does release 10th grade growth percentiles.
Will all students be included in growth reports?
No. As noted above, students in grades 4 through 8 who have two or more consecutive years of MCAS results will be included in growth reporting. In addition, students in grade 10 who have attended Massachusetts public schools in 8th, 9th, and 10th grade will be included. School-level growth reports give users the option of including students who were tested in the same school in which they were enrolled at the beginning (October 1) of the school year, and students who were enrolled after October 1st.
Any student who took the MCAS-Alt at any point during the student's two most recent MCAS administrations will not be included in growth reports. Additionally, MCAS retests are not included in the calculation of student growth percentiles.
What do growth reports show that standard MCAS and AYP reports don't?
School and district growth reports display information about how much academic progress students made in relation to their academic peers (students with a similar MCAS test result history).
MCAS reports present information about the performance of students at the end of each school year, displaying the distribution of students performing at each of the MCAS performance levels.
Adequate Yearly Progress (AYP) reports display information about how close a school or district is to helping all students reach or exceed proficiency. While the measure of improvement on AYP reports is correlated with individual student growth, it is focused on comparisons of grade-level cohorts (e.g., this year's 4th graders compared to last year's 4th graders). In addition, AYP reports do not measure any change in performance for students at or above the Proficient performance level.
Is growth a better measure of student performance than MCAS or AYP?
No. It simply answers a different question. If you want to know how well a student performed on the standards for mathematics or ELA by the end of 6th grade, the MCAS scaled score and performance level are the best indicators. If you want to know whether a school is on target for having all of its students Proficient by 2014, AYP reports are the right measure. If you are trying to determine how much a student's performance has changed from 2007 to 2008 relative to the student's academic peers, the growth model is the best indicator. A more complete understanding of performance can be obtained by using all three measures.
Will growth data be used for accountability (AYP) determinations?
Not initially. As of this printing, the Department is using growth data only as a supplement to the other MCAS results we already provide. The Department may decide to submit a request to the U.S. Department of Education to use growth in accountability decisions at a later date.
How will growth data be disseminated to districts, schools, teachers, and the community at large?
Growth data will be accessible to districts through a number of media: School and District Profiles, the District Analysis and Review Tool (DART), and the Department's Education Data Warehouse (EDW) all contain growth data. Through the EDW, districts can produce student-level reports for distribution. All other reports on Profiles and in the DART are aggregated to the subgroup, school, and district level using the median student growth percentile.
Will the state provide growth data for high schools? If so, how are the calculations made and how should the data be interpreted?
Yes. The fall of 2009 provided the first opportunity to calculate growth for high school students, because the growth model requires at least one year of prior data (two year's prior, if available), and there is no 9th grade test. Therefore, we must use grade 7 and/or 8 tests as the prior years. The grade 7 mathematics and grade 8 ELA tests were introduced for the first time in 2006. Consequently, 2009 was our first opportunity to compute student growth percentiles for 10th graders using two prior years of data.
Due to the extra year between grades 8 and 10 MCAS administrations, there are a few things to keep in mind when interpreting the 10th grade growth measure.
- The individual student growth percentiles represent two years of growth for each student (from the 8th grade to the 10th grade) and are, therefore, attributable in part to experiences and variables from the end of 8th grade, through 9th grade, and through most of 10th grade.
- The school and district level median student growth percentiles do not represent only those students who remained in the same school or district during grades 9 and 10. Thus, a student who arrived at your school or district for the first time in 10th grade will be included in the calculation. Any interpretation must therefore take into account that some of the growth or lack of growth is attributable in part to the range of student experiences since the end of 8th grade.
Grade 10 student growth percentiles tend to vary more than growth percentiles at other grade levels. This happens because a large majority of 10th graders reach the Proficient performance level on the MCAS and are therefore concentrated at the top of the scale. Differentiating between these scores is challenging because relatively small differences in performance seem larger when translated into student growth percentiles.
What additional information will the Department provide to teachers, administrators, and other education stakeholders on how growth data is calculated and how to use it effectively? Where can I find this information?
Resources including videos, links to data, this Interpretive Guide and FAQ, and a quick start guide for generating growth reports in the EDW are located both at MCAS: Growth Model and within the Data Warehouse. Questions not answered by these materials should be emailed to firstname.lastname@example.org.