This page provides an overview of student growth percentiles, a new method of measuring student academic growth introduced by OSPI in March 2013. This page will answer the following questions:
A student growth percentile (SGP) describes a student’s growth compared to other
students with similar prior test scores (their academic peers). Although the
calculations for SGPs are complex, percentiles are a familiar method of
measuring students in comparison to their peers.
Washington’s state assessments are not vertically scaled. This means the
different MSP grade level tests do not combine to form one long yardstick for
measuring growth in math or reading from one grade level to the next. Therefore
we cannot measure a student’s absolute growth by comparing last year’s scale
score to this year’s. Instead, we can measure student growth by calculating
student growth percentiles that indicate the amount of growth a student made in
a testing subject over the course of one year, relative to their academic peers.
The student growth percentile allows us to fairly compare students who enter
school at different levels. It also demonstrates a student’s growth and academic
progress, even if she is not yet meeting standard.
A student growth percentile is a number between 1 and 99. If a student has an
SGP of 85, we can say that she showed more growth than 85 percent of her
academic peers. A student with a low score on a state assessment can show high
growth and a student with a high score can demonstrate low growth. Similarly,
two students with very different scale scores can have the same SGP.
Student growth percentiles are measured by using a statistical method called quantile regression that describes the relationship between students’ previous scores and their current year’s scores. For more discussion of the SGP model:
For SGPs, a student is compared to his/her academic peers. A student’s “academic
peers” are all students in Washington State in the same grade and assessment
subject that had statistically similar scores in previous years. In other words,
they are students that have followed a similar assessment score path. A
student’s growth percentile represents how much a student grew in comparison to
these academic peers.
The median growth percentile summarizes student growth percentiles by district,
school, grade level, or other group of interest. The median is calculated by
ordering individual student growth percentiles from lowest to highest, and
identifying the middle score, which is the median. The median may not be as
familiar to people as the average, but it is similar in interpretation – it
summarizes the group in a single number that is fairly calculated to reflect the
group as a whole. (Medians are more appropriate to use than averages when
summarizing a collection of percentile scores.)
The two year target represents the amount of growth a student will need in the next two years in order to reach or remain at or above proficiency. The two year target helps us not only to look at how much growth a student has made, but what amount of growth is enough to get them where they need to be. For more details on this topic, please see the “Two Year Target & Catch-Up, Keep-Up Definitions” slides on the OSPI Student Growth Percentiles webpage. The two-year targets are based on the current Washington State assessment program. These targets could change when the state shifts to the new Smarter Balanced Assessment.
A student is considered to be “Catching-Up” if they scored in the Level 1: Below Basic or Level 2: Basic ranges in the previous year and their SGP is greater than their two-year target. This means that they are on track to reaching proficiency within the next two years. A student is considered to be “Keeping-Up” if they scored in the Level 3: Proficient range in the previous year and their SGP is greater than their two-year target. This means that they are on track to stay at or above proficiency within the next two years. For more details on this topic, please see the “Two Year Target & Catch-Up, Keep-Up Definitions” slides on the OSPI Student Growth Percentiles webpage.
Yes, because we are measuring normative growth, (i.e. students are being
compared to their academic peers taking the same assessments), it is possible to
calculate growth reliably. Student growth percentiles do not require identical
tests or scales from year to year.
Yes. Students that typically have high scores on state assessments will be
compared to all other students in the state that also have high scores. The data
show that even students that score at the top of the scale will have varied
performance the next year, so the model allows us to identify growth for
students at the upper end of the scale.
The students included in the student growth percentile calculations are those
that attend public school and took a state assessment during the spring
administration. Certain test types and categories of students are excluded from
this comparison group. Only students that have at least two years of consecutive
scores are included. For example, if a student has a score in 5th grade, but not
in 6th grade, she would not be included in the analysis. All available scores
are used in the model, as long as they are consecutive. Washington’s student
growth percentiles are calculated using assessment data beginning in 2005-06.
All students in the state that have valid and consecutive test scores in the
same subject and grade form the norming population for the calculation of the
SGPs. Each year that student growth percentiles are calculated, the norming
population will consist of students enrolled and tested in that subject and
grade during that school year.
If students tested in the grades listed below, in addition to testing in at
least one year prior, they will receive a growth percentile.
Although the table lists the testing grade of students that would receive a student growth percentile, these students are now most likely in the next higher grade.
SGPs will not be calculated for Science, Writing, or EOC Biology.
SGPs for the end-of-course assessments are calculated in a number of ways.
- If a student took the EOC 1 in 7th, 8th, 9th or 10th grade, their MSP math score(s) from the previous year(s) are used to calculate growth. If a student took EOC 1 in 10th grade, their 8th grade MSP score is used.
- If a student took the EOC 2 in 9th or 10th grade, and they took the EOC 1 in the previous year (8th or 9th grade, respectively), their SGP is calculated using the EOC 1 score as a prior, as well as any consecutive MSP Math scores previous to their EOC 1 score. If a student does not have an EOC 1 score in a previous year, and they do have an MSP Math score in 8th grade, this score is used and their 10th grade EOC 2 SGP represents two years of growth.
Students that take the EOC 1 and EOC 2 in the same testing window or the same school year, even if different semesters, will not receive an SGP that uses EOC 1 as a prior year score for the EOC 2.
Growth percentiles have been calculated for subjects in 10th grade even though
those students would not have had a prior year score. SGPs for students who test
in 10th grade are less straightforward, because of the 9th grade test gap and
thus one must use caution when interpreting those scores. One needs to say “how
has this student done over the past TWO years, relative to academic peers using
8th grade and prior scores”. Attributing 10th grade SGPs to a teacher is not
recommended, but the information is useful in evaluating a student’s progress
Student growth percentiles are primarily a descriptive model, telling us what
amount of growth a student has made over the last year. This growth model is not
a value-added model; it does not attempt to separate a teacher or school effect
on student learning. SGPs can, however, help answer the following questions
- Is my child growing adequately toward meeting state standards?
- Is my child growing more or less in Math than Reading, relative to other students in the state that scored similarly?
- Did my students grow adequately toward meeting state standards?
- How much growth do my students need to become proficient?
- Are there students with unusually low growth who need special attention?
- Are our students growing adequately toward meeting state standards?
- How does the growth of students in my school compare to students in other schools?
- Are students in different grade levels within my school growing similarly?
OSPI released the first round of student growth percentiles percentile data in
March 2013. SGP data for 2013 was posted to WAMS in October of 2013. Student
growth percentiles have been calculated and provided for the three school years
of 2010-11 through 2012-13. The following documents have been made available to
- Individual student reports, including student growth percentiles charts for
math and reading
- School-level reports that show individual students’ growth percentiles; one
report for each subject/grade combination
- District-level reports that show the median growth percentile of each school
- School growth summary reports
- Excel data files that include SGPs at the student-level and aggregate data
at the school, district, and student group levels
Download examples of these reports.
Districts will receive electronic versions of SGP reports. These reports and
excel files will be available to districts in the Washington Assessment
Management System (WAMS) accessed through the EDS portal. District assessment
coordinators can download the data by clicking on ‘Profile’, then ‘File
Downloads’. The data released in the spring for school years 2010-11 and 2011-12
are located under the 2012 Administration. The 2013 SGP data files and reports
can be accessed through the EDS portal of the Washington Assessment Management
System (WAMS) application. The files are located under Profile > File Downloads
> 2013 Administration > 7. Student Growth Percentiles (SGP).
OSPI will report student subgroup, school and district-level median student growth percentiles publicly in fall 2013 on the OSPI State Longitudinal Data System (SLDS) K-12 Data & Reports website. From the K-12 Data and Reports homepage, click on “Static Data Files”. Next click on the “Assessment” menu item then scroll down to find the SGP files and reports.
In the spring of 2013-14, OSPI will launch an interactive website that will have visualization tools for the SGP data. This website will show school and district aggregations to the public user and student-level data for educators and administrators.
At this time, it is at the discretion of Washington school districts whether or not to distribute student growth reports to families and students.
The State Board of Education’s Achievement Index School median student growth percentiles are one of the new measures in the revised State Board of Education’s Achievement Index. The Index design is soon to be under review by the US Department of Education. For more information, please view this short summary video developed by the SBE that summarizes changes to the index as well the current status. Please visit the SBE Achievement and Accountability Workgroup’s (AAW) webpage to view the draft index design documents that demonstrate how SGPs, proficiency and college and career readiness will be used to determine a school’s index rating.
Teacher Principal Evaluation Project (TPEP) Districts may eventually choose to use student growth percentiles as a component in teacher evaluation. SGPs could inform teacher evaluations if schools attribute individual students to specific teachers. OSPI advises against using student growth data for evaluation of performance during the 2013-14 school year and recommends waiting until the 2014–15 school year. For more details on the use of student growth percentiles in teacher evaluation, please see the TPEP Statement on Student Growth Percentiles. More information on this topic will be available by visiting the TPEP Web site.
Washington State student growth percentiles were developed by Damian Betebenner of the Center for Assessment (NCIEA). They were first developed in Colorado for use in their Accountability framework in 2007. Student growth percentiles have been adopted by 23 other states, and are under consideration in many more. To view a map of states using SGPs.
Background on Student Growth Percentiles:
OSPI Webinar: Introduction to SGP (36-minute video)
Growth Model Comparison Study. Council of Chief State School Officers (CCSSO).
The Colorado Growth Model – SchoolVIEW. Colorado Department of Education.
The DC Schoolwide Growth Model– Frequently Asked Questions . DC Public Charter School Board.
Growth: Measuring Idaho’s Students. Idaho Department of Education.
Student Growth Percentiles. Seattle Public Schools (PG & E Video Series).
Please note: Seattle Public Schools controls for additional student characteristics in their model, whereas the model used by OSPI only controls for students score history.
Articles Cited & Additional Technical Resources:
Betebenner, D. 2011. A Technical Overview of the Student Growth Percentile Methodology: Student Growth Percentiles and Percentile Growth Projections/Trajectories. The National Center for the Improvement of Educational Assessment.
Cade, B and Noon, B. 2003. A gentle introduction to quantile regression for ecologists. Frontiers in Ecology and the Environment. 1(8): 412 – 420.
Koenker, R and Hallock, K. 2001. Quantile Regression. Journal of Economic Perspectives. 15(4): 143-156.
Yen, W. M. 2007. Vertical scaling and No Child Left Behind. In N. J. Dorans, M. Pommerich, & P. W. Holland (Eds.), Linking and aligning scores and scales (pp. 273-283). New York: Springer.
OSPI is very interested in hearing your questions, recognizing student growth percentiles are a new and complex method of assessing student growth percentiles. We look forward to continued communication. Please email your questions and feedback to firstname.lastname@example.org