Using Data

Data utilization strategies have been developed to help guide teachers in making instructional changes. These are guidelines and should NOT be viewed as imperatives. Teachers must consider the multiple variables affecting the student and his or her academic program and then use their professional judgment before making instructional changes. Three different data utilization strategies are commonly used to guide teacher's decisions. The goal-based strategy requires less technical knowledge and is easier to implement. This strategy calls for a change in the student's instructional program any time a certain number of consecutive data points (e.g. four) fall below the goal line.

The Intervention Oriented data utilization strategy compares the effectiveness of each intervention by examining the trend (slope) of the data in each successive phase. Systematically make changes in the student program after a minimum of 9-12 or maximum of 16-20 data points. Continuously search for interventions that will "close the gap" (lessen the discrepancy) between student and average level peers.

The Goal/Intervention Approach uses the same procedure involved in the intervention oriented procedure, except that a long-range goal is set and drawn on a graph. One might compare the rate of student progress (slope) to the long-range goal, as well as to the rate of progress during the previous intervention strategy.

A common method for evaluating the trend (slope) or average rate of growth for the student is to use the split middle technique. These data are divided into quarters and then each half of the data set into halves from low to high score. The procedure is slightly different for an even number of data points and an uneven number of data points.

Example of the split middle technique for an even number of data points:

1. Divide the data into two equal parts, chronologically (from left to right).
2. Split each part in half.
3. Find the median point for each part from low score to high score (from top to bottom).
4. Move each median point over to the vertical mid point to make crosses as shown below.
5. Connect the crosses with a straight line. This is the student's trend (slope) or average rate of growth.

Example of the split middle technique for an odd number of data points:

1. Divide the data into two equal parts, chronologically (from left to right).
2. Split each part in half.
3. Find the median point for each part from low score to high score (from top to bottom).
4. Move each median point over to the vertical mid point to make crosses as shown below.
5. Connect the crosses with a straight line. This is the student's trend (slope) or average rate of growth.

Once the trend line has been drawn on the graph to summarize progress throughout an intervention phase, a simple procedure can be followed to calculate a numeric value for this line. The numeric value is useful for summarizing and communicating the student's trend (slope) or rate of progress. This allows professionals to be more precise in describing the rate of growth.

1. To begin, select any two vertical lines for which the trend line intersects (representing days).
2. Find where the trend line crosses the first Monday line.
3. Find where the trend line crosses the second Monday line.
4. Subtract the smaller number from the larger number. 
       30
      -20
       10
5. Divide the number by the number of weeks that the Mondays are apart of the graph. 
       10 ÷ 2 = 5
6. Trends can be either ascending or descending. Thus the numeric values could be either positive or negative integers, e.g. + 5 or - 5.