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12/10/2013

Gradebook Summary Trend

Tags: gradebook, Summary, Trend, portal, Portals, Parent, Student

We're fans of trends around here at Aeries.  However, the trends that get us excited do not involve the latest celebrity nor have anything to do with clothes.  No, the trends that get discussed around our water cooler have more to do with student data and performance and how we can help present that data more effectively.  The Aeries Gradebook is one of many fertile data fields ready for the harvesting.  One trend that is currently available is the Overall Score Trend.

This trend is especially valuable to parents and school educators because it can be used as a tool to help the student see how their performance is affected by the scores of their assignments.  To see the detail, simply click on the icon and you will be presented with a graph showing both the overall trend in blue and each individual assignment score in yellow.  The overall trend serves as an indicator of the overall performance in the gradebook and how assignments over time affect the overall grade.  It is very easy to see how a single missed assignment can greatly impact the overall score and trend of a student's performance.

When you click on the icon, you can see the full graph:

Figure 1

If you hover over an individual assignment or overall score, a popup will give you more information for that specific item:

Figure 2 - Assignment Detail on mouse hover

Figure 3 - Overall Score Detail on mouse hover

The trend uses a linear regression algorithm to predict what the next overall score for the student will be based upon the historical performance of the student.  To be exact, we use either the past 10 overall scores, or the past 25% of overall scores, whichever has the greater number of scores to analyze.  Linear regression is a fancy name for prediction.  It takes in a range of numbers that are ordered in a specific sequence, then asks for what the next score is going to be and returns the variance or difference between what the range of scores should be and what the next score is.  This difference tells you how far away the next number is from the slope or trend of the previous scores.

Let's look at an example.  Nick is taking Algebra and has the following scores on his assignments:

Assign #

1

2

3

4

5

6

7

8

9

10

11

12

Possible

35

10

5

100

10

27

10

5

40

10

40

20

Earned

26

10

5

67

8

20

7

0

14

8

32

15

Score %

74.2

100

100

67

80

74

70

0

35

80

80

75

Overall %

74.2

80

82

72.5

72.7

70.8

64.8

65.4

67.4

67.9

His overall scores will be calculated by adding up all the points earned, dividing that by adding up all the points possible, and multiplying that by 100.  Therefore, the first of the 10 overall scores used will be 74.2% because 26 ÷ 35 is 74.29%.  The second overall score will be 80% since (26 + 10) ÷ (35 + 10) = 80%.  The third overall score will be (26 + 10 + 5) ÷ (35 + 10 +5) = 82%, and so on.  Taking this set of overall scores, we can now plot them on a graph to come up with the slope seen in figure 1.

Using our predictive algorithm (linear regression), we can compute that the next value can be predicted at 64.18.  We compare that number against the average of the last four overall scores (64.8 + 65.4 + 67.4 + 67.9) ÷ 4 = 66.44 and we can see that 64.18 is less than 66.44, so this gradebook grade is trending down.  The trend is down even though we've seen some leveling out lately.  The scores at the beginning really set the stage for the trend.  This could all change depending on the next couple of assignments, though.  When your score is high, one missed assignment will cause your grade to trend down.  That is why it is possible for a student to have an overall score of 96% in the class and still be trending down.

To allow for some wiggle room, we have the trend difference threshold set to 1%.  This is so that if the predicted trend is 91% but the average of the past four overall scores is 93%, then it will show a down trend.  Conversely, if the predicted trend is 91.5% and the average of the past four overall scores is 90.6% (0.9% difference) then the trend will "stay the same."

Hopefully, this has been helpful in understanding how we calculate the trend.  You can see that we put a lot of thought into this and hope that this can be used as one measurement to help keep students on track for success.

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