Is it ok to base an educational decision for a student on one test score?
When using data to guide decision-making in almost any field it is important to recognize the limitations of a single data point. This is especially true in education where we are responsible for the well-being and learning of our students.
A single test score gives a very limited picture of how a student is progressing. One of the fundamental principles of Track My Progress is the use of multiple data points over time to get a fuller picture of how a student is progressing and using that fuller picture to guide our educational decision-making for the student.
Let's look at an example from Track My Progress data. In the below graph you see the reading test of a student tested in the spring of third grade. She has a scale score of 615 which is at the 19th percentile and based on this school's Response to Intervention protocol indicates she is at-risk (i.e. below the 20th percentile).
Fortunately, this is not the only test score this school has for the student. The graph below includes all data points and provides a different picture of how this student is progressing.
When we see five data points, instead of the one presented initially, we see a more complete story about how the student is progressing which could lead to some different educational decisions than when we only use one data point. The student's score of 640 in the fall of third grade is at the 40th percentile. The student's score of 706 in the fall of grade four is at the 39th percentile. This student is making expected progress in reading and appears to have done unusually poorly on one out of five tests.
Sometimes we do not have multiple data points over a period of years and we must be response to a student's needs and make a decision on whether additional or differentiated instruction is required. However, we always have additional data points when we consider sources like attendance, class participation, homework quality and class quiz scores. The principal is to always coordinate data with other sources and when possible progress over time data to get a fuller picture of student progress.