Traditional approaches to progress monitoring were built on research indicating that at least 12, but sometimes more, data points are needed prior to drawing conclusions about the effects of an intervention. Recent research by Christ and Desjardins (2018) indicates that it’s possible to predict a student’s progress trend with 6 data points.
Limitations of Traditional Methods
With a sufficient number of data points, teachers can use existing data to predict the future trend of a student’s progress during a specific intervention. Most published progress monitoring tools use a method known as the Ordinary Least Squares Regression (OLSR). Prior research indicates that this method requires at least 12 data points to predict future scores. A significant limitation of this method is the amount of time necessary to collect sufficient data. For example, if at least 12 data points are needed and progress is monitored weekly, it will take at least 12 weeks to have enough data points to predict an accurate trend. If progress is monitored every other week (i.e. bi-weekly) then 24 weeks would be needed. This means that more than a quarter of the school year is needed before the effects of an intervention will be known.
To address the time constraints present in traditional progress monitoring trend calculations, Christ and Desjardins (2018) documented that a different method for calculating the trend of a student’s progress data is possible. This alternative uses conditional probability to estimate future outcomes and is based on the work of statistical pioneer Thomas Bayes. Using Bayesian methods, a reliable trend can be identified with as few as six data points collected either weekly or bi-weekly (i.e., every other week). This method allows teachers to interpret student data earlier in the school year and change interventions more often, if needed.
Conditional probability involves using calculations of prior data trends from large numbers of students monitored with the same measure as a way of predicting what data trend is likely for an individual student. By using prior data from large numbers of other students to predict future performance, the amount of time needed to calculate a trend line is shortened.
FastBridge Projection Line
Illuminate Education is the first publisher to incorporate Bayesian analysis into its progress monitoring tools. In FastBridge progress monitoring reports, the Bayesian analysis is referred to as the FastBridge Projection™ line. Due to the necessity of a sufficient amount of prior data in order to calculate predicted scores, the FAST Projection™ is available for the most commonly-used progress monitoring measures, including:
- FastBridge CBMmath Automaticity™
- FastBridge CBMreading English™
- FastBridge CBMreading Spanish™
- FastBridge earlyMath™
- Decomposing DC-1
- Numeral Identification NI-1
- FastBridge earlyReading English™
- Decodable Words
- Letter Names
- Letter Sounds
- Nonsense Words
- Onset Sounds
- Word Segmenting
- Sight Words 150
Progress Monitoring Reports with FastBridge Projection™ Line
Below is an example of a Progress Monitoring report with the FastBridge Projection™ line shown.
In this example, there are 6 data points. The student’s goal is shown with a dashed line, and the student’s trend based on existing scores is shown with a solid blue line. The FastBridge Projection™ line is shown as a dotted line that extends after the date of the last data point. In this case, the solid blue line suggests that the student is not on track to reach the goal, but the FastBridge Projection™ line indicates that the student will reach the goal. Using the FastBridge Projection™ line the teacher and team decide to maintain the current intervention and continue to review the data to confirm that the student remains on track to reach the goal.
Turning the FastBridge Projection™ Line Off and On
As with other features of the FastBridge ™ progress graph, the FastBridge Projection™ line can be turned off. This is done by clicking on the words FastBridge Projection™ line in the legend below the graph. Here is the same graph with the FastBridge Projection Line™ turned off.
The FastBridge Projection™ line is turned on by default for all progress graphs where it is available. If it is turned off, it can be turned back on by clicking on the same text in the legend.