Student Growth Percentiles

Student Growth Percentiles

With all of the changes going on in New Jersey schools, specifically from Achieve NJ, it is important for educators to understand the new methods being used to determine student achievement. Student growth percentiles (SGP) are now one of the multiple ways to track student growth, which in turn, reflects on teacher and principal effectiveness. With New Jersey being on the forefront of improving educational practice, the process of evaluating student growth is becoming more precise and also varies by grade level. In grade levels 4-8, students take a multi-year assessment (NJ ASK) on the subjects of language arts literacy and math. From these assessments, student growth percentiles are created and give educators a novel way of analyzing student growth. SGPs quantify student achievement by comparing scores with other students on the same academic level. The comparisons can give teachers, parents, and students an alternate view of  determining whether or not a student is progressing appropriately for their grade level. By using these percentiles, it is believed that schools can better determine if certain practices are effective, as well as the teachers who are implementing them.

 The use of SGPs has created various questions about what the scores mean to academic achievement in our schools. In recent years, value-added analysis models have been used to rate student achievement. These analysis models use intricate statistics in order to show student growth by analyzing a specific teacher or school. These methods attempt to show how much a student/ group of students progressed due to the teacher/ school contribution. Despite the fact that these tools may sometimes be a useful indicator of effective practice, there fails to be one main question: How much growth did a student actually make?

The absence of a measurement tool for student growth has led to the emergence of SGPs, or student growth percentiles. Student growth percentiles are a statistical method of showing how much a particular student progressed in comparison to his/her academic peers. In this circumstance, academic peers are students who have scored similarly on standardized tests over the past years and are on the same academic path. Below I have included a brief explanation taken from the RAND Corporation’s program on SGPs:

"For example, if Adele scored 263 on last year's test, her score at the end of this year would be compared with the scores of all the other students who scored 263 last year. Adele's SGP would be her percentile rank (from 1 to 99) within this group of similar peers. If Adele's SGP is 50, it means that her growth in test scores is right in the middle: Half of the similar students who scored 263 last year scored higher than she did this year, and half of them scored lower."

The use of SGPs can show progress on a larger scale in relation to students who are also moving along the same path. These scores answer the general question of “Is            progressing like they should be?” Along with providing a simpler way of showing academic progression (or lack thereof) for a student, SGPs are now also a large portion of the data used in teacher evaluations. It is important to note that due to the years the NJ ASK is administered, as well as the subjects being tested, SGPs apply to language arts and math teachers in grades 4-8 only. A teacher’s “score” is taken from the median growth percentile from a group of students. The median growth percentile or MGP is the middle score in a group of students. Instead of creating an average of the percentiles, the median score is used because it shows the growth of a middle or “average” student. This is said to be a more accurate depiction of a typical student because the middle score is not greatly affected by outliers in either direction (either a student doing exceptionally well or poor). For the teachers that get evaluated on SGPs, their score accounts for 30% of their yearly evaluation. Although this may seem like it puts a great amount of pressure on teachers, they are not the only ones who are affected, school principals are evaluated based on these scores as well.  Due to new educational standards from Achieve NJ, principals are also now critiqued based on how well students perform on standardized tests.  Their “scores” are similar to the MGP used to evaluate teachers, but instead of a particular class, the calculation uses all applicable students in creating their MGP.

Unfortunately, much like other analysis methods, SGPs are not flawless in either determining student growth or teacher effectiveness. The median scores used for evaluation do not account for differences in student characteristics. Additionally, SGPs, like value-added modeling, do not specify what exactly caused the improvement. Since the scores do not show specific causes of improvement, it is difficult to determine whether or not a different student would have made the same improvement in the same conditions. SGPs may be a simple method to understand scores, however, when looking at the variables that come into play that affect student improvement, rating students and teachers based on these scores may be altogether too simple.  Learning is an extremely dynamic process, and by just comparing numbers, we may not be accurately analyzing a particular student’s progression through school. Also, as past research has shown, standardized testing may not always be the best indicator of learning. Since standardized testing has flaws in it self, by evaluating teachers on exam results we may not be accurately scoring how effective a teacher is in the classroom, but how well the student learned to take the exam.

 Since Achieve NJ has only recently been introduced in the 2013-2014 school year, it will take some time for schools to accurately assess whether the new standards are making positive changes. Additionally, because SGPs are now a component of evaluation for "tested subject" teachers, it is essential that educators understand the meaning of scores and how they can be used properly. Hopefully, with proper use, the incorporation of SGPs can become a helpful tool in improving educational practice. Despite some of the flaws behind SGPs, by giving a new perspective on improving student achievement, schools may be taking a step in the right direction.

Below are the two main articles that I used which are provided through the State of New Jersey - Department of Education Website: www. State.nj.us

Betebenner, D. (2011) An Overview of Student Growth Percentiles, National Center for the Improvement of Educational Assessment.

Betebenner, D. (2011), White paper from the National Center for the Improvement of Educational Assessments (NCIEA): 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.