About the Data
Background on Growth
Growth is an important measure that can be used to evaluate the pace of students’ academic progress. Growth reports help educators, parents, and the public answer questions about student progress over time, and whether that progress is reasonable or appropriate. This is important information above and beyond examining student achievement at a single point in time that traditional test reporting provides.
The growth presented in this dashboard is called Student Growth Percentiles (SGPs). Individual student-level SGPs are calculated by comparing the amount of academic progress a student has made from one year to the next to that made by other Wisconsin students with similar performance histories on annual statewide assessments.
Sample SGP Scenario
Consider an example student named Simon. Simon is in sixth grade this year and achieved a scale score of 370 on the statewide assessment in English language arts (ELA) this year. Last year, in fifth grade, Simon scored a 300 on the ELA exam, meaning that Simon’s scale score increased by 70 points between last year and this year. A simple comparison of this scale score growth could be made between Simon and all other students in the state, but this would ignore important differences between assessments, especially specific grade-level differences, and the potentially different degree of difficulty in making the same scale score growth from different starting scores. It would be a faulty comparison. SGPs solve this problem.
SGPs place Simon’s score growth in the context of other sixth graders with similar score histories. That is, his 6th grade performance is compared to other 6th graders whose 5th grade score was similar to Simon’s 5th grade score. Up to five years of prior test scores are used to establish Simon’s comparison group. For Simon, this means that his fifth-to-sixth grade growth comparison group had similar test scores as Simon not only in fifth grade, but also in fourth and third grades.
Low, High, and Typical Growth
SGPs produce a percentile ranking of the magnitude of scale score change for a group of students with a similar starting point. SGPs, like all percentiles, are on a scale from 1 (lowest growth) to 99 (highest growth). Suppose Simon’s SGP is 63. This means that his change in scale score of 70 points was at the 63rd percentile for the group. In other words, Simon grew at a rate greater than or equal to 63 percent of the students who started at the same place.
For school-, district-, or subgroup-level reporting, the mean SGP of students in the school/district or subgroup is presented. The mean student growth percentile for a group is calculated by pooling all of the individual student growth percentiles and identifying the mean, or average. The mean (average) is used as a representation of typical growth for that selected group of students.
As mentioned above, aggregate SGP graphs display mean SGP. When viewing reports by demographic subgroup, each bubble on the graph represents one subgroup. Bubble size is determined by the size of the subgroup; the larger the bubble, the larger the subgroup. The horizontal axis of the graph displays the mean student growth percentile -- the further the bubble is to the right, the higher the mean student growth percentile. The vertical axis displays the percent scoring proficient or advanced on the statewide assessment in that year -- the higher the bubble location the greater the percentage of students scoring proficient or advanced.
Data points toward the bottom left of the graph represent both low achievement and low growth. Data points in the upper right of the graph represent both high achievement and high growth.
When you hover your cursor over the bubble you can see the number of students, mean student growth percentile, and percent proficient and advanced.
Authorized users can drill down to student details that provide multiple additional data points. The detail provides the growth interval (e.g. 6th to 7th grade); student demographics; each student’s growth percentile and corresponding growth level (high, low, typical); scale score data and performance levels; attendance rate in the growth year and DEWS risk (when applicable).
SGPs have been produced since the 2008-09 school year. However, the dashboard does not include an option to view reports for the 2014-15 school year. DPI did not calculate or report SGPs for the 2014-15 year because it was the only year that the Badger Exam was administered. Having only a single year of student performance on this assessment -- in which statewide performance was quite different from either the WKCE, which preceded it, or the Forward Exam, which followed and is currently administered -- presented data challenges related to validity and reliability. Because the 2014-15 year is omitted from the student-level growth reports, the horizontal axis jumps directly from 2013-14 to 2015-16.
Note that though the 2014-15 Badger year is omitted from the graphic, the SGP displayed for 2015-16 was calculated using up to five years of student test score history, including the Badger year. While the 2014-15 Badger performance levels were incorporated into the test score histories, 2014-15 growth percentiles themselves were not generated.
Since the SGP dashboard reports individual student-level information, as well as grade-level, subgroup, and school-wide growth, the data can be a powerful source of evidence for a wide range of stakeholders.
- Individual SGPs can and should be shared with parents, to enrich the picture of their child’s performance.
- Grade-level and subgroup SGPs should be reviewed by educators and data teams, to identify areas of success and those targeted for improvement. SGP data can be used in educators’ SLOs process.
- Administrators should incorporate school and district-wide SGP data into their continuous improvement efforts.
- DPI has proposed using mean SGP data in the proposed federal accountability system, starting in December 2018. Please note that SGPs are not used in the Accountability Report Cards (which are part of the state accountability structure), because value-added growth scores are required by state law to be used in the state system. Value-added scores provide another way of looking at student growth aimed at evaluating school and district effectiveness.
The guides below are meant to provide assistance in reading and interpreting SGP reports. For more information on measuring growth and how growth data are used in Wisconsin, please see the Academic Growth webpage.