If you have ever worked with state assessment data, you may be familiar with the term student growth percentiles (SGPs). SGPs are used to identify relative performance in relation to academic peers. A student with a high SGP indicates that they scored higher than or equal to the highest 75 percent of their academic peers on this year’s statewide assessment. SGPs are based on the principle that students who perform well at one point in time will likely be able to continue to perform well over time, especially if they can improve their achievement levels with support from teachers and other school staff.
Often times, schools and districts report SGPs at the school/district or student group level. This reporting allows for comparisons of student performances across the system. In addition, it is common for SGPs to be reported by subject area so that teachers can compare their own instructional practices to the best performing teachers in their field.
When comparing SGPs at the school/district and student group level, it is important to remember that these are averages. A single student can have a range of SGPs from high to low due to their individual learning needs and unique performance trajectory. Regardless, the SGPs for any given student can be interpreted to indicate that they are performing above or below expectations and that there is a need for additional targeted supports.
SGPs are calculated on a scale from 1 to 99 with lower numbers indicating lower relative growth and higher numbers indicating greater relative growth. A SGP of 78 indicates that the student demonstrated growth better than 78 percent of their academic peers. For example, Students A and B both had high MCAS scores this year in a particular subject area. However, Students A had a high rate of growth and was able to maintain their high score while Student B did not demonstrate the same level of growth and dropped below the 70th percentile.
SGP analyses are meant to be straightforward once the necessary software/hardware is installed and the data is prepared correctly. In fact, most errors that occur when using SGPs revert back to issues in the initial stages of data preparation.