Why graph data?
The value of graphing data is that it gives a visual depiction of the information that, when done well, allows the reader to make quicker meaning of the data. This is particularly true when you have a lot of data that cant be quickly assimilated in a table format. For example, the following data in a table has been graphed. Which gives you the most information? They both contain the same information, but the graph leads you to conclusions much faster that an examination of the data in the table.
What graphs are useful?
You select the type of graph you want to use based on the information you are looking for. Popular graphs include bar graphs, line graphs, and pie graphs. A graphing tool is a quick way to create presentable graphs of your data. You may also want to consider a box and whiskers graph. In an Educational Leadership article entitled, Developing Data Mentors, authors Beverly Nichols and Kevin Singer describe how box and whiskers plots could be used to report data collected over time, such as pre and post tests or parallel practice activities. By simply averaging scores from pre and post test results, the teacher would learn that performance of her class as a whole had improved. Because the box plot clearly delineates low and high scores, the median, and the first and third quartiles, the teacher could see that performance had improved for low, medium, and high performance levels. In the graph shown, the low score had moved up almost 20 percent; the first quartile on the post test was roughly equivalent to the third quartile on the pre-test. The teacher had visual verification that she was reaching all of her students. If you need help constructing a box and whiskers graph, listen to psycometrician Bill Shaffer explain the process.
Another way to get a quick visual picture of who needs additional support in your classroom is to color code your data. For example, if you used three categories to define student performance in your grade book (e.g., basic B, proficient P, and advanced A), you could color code all the Bs red, all the Ps blue, and all the As yellow. This would allow you to quickly pick out who was progressing and who needed additional support.
Why graph classroom data?
You graph classroom data to help you analyze how well your class is learning, what you need to re-teach, how groups of students are performing, how well each of your students is progressing, and who needs what interventions. To illustrate useful ways to graph your classroom data, we have created a sample gradebook (based on a monitoring tool), identified questions you might ask about your data, and graphed the data to help you answer those questions.