TrendBox is a very powerful mechanism to visualize performance over time. Common uses include incidents assigned per week, by either technician or assignment group. The reason the TrendBox is superior for visualizing performance is due to six key factors.
- Maximum
- Median
- Upper Quartile
- Lower Quartile
- Mean
- Minimum
In the explanations, we will reference a theoretical TrendBox that is a report of incidents assigned to each tech, per month. Our theoretical tech will have worked the following number incidents per month:
| Month 1 | Month 2 | Month 3 | Month 4 | Month 5 | Month 6 |
| 1 Incidents | 3 Incidents | 5 Incidents | 2 Incidents | 6 Incidents | 5 Incidents |
Maximum
The maximum value is, as the name implies, the highest count reached during the time frame. In a report that trends per month, it would be the month where the technician had the most assigned. In our example data set, the value would be "6 Incidents" in month 5. This is indicated by the top 'whisker' on the graph.
Median
The Median represents the center most value, if all the interval counts where ordered from minimum to maximum. In this case, it would be 1,2,3,5,5,6. The median would be 4, because it is an even data set ((3+5)/2). If the count was odd, it would be the exact center value.
Upper Quartile
The upper quartile is essentially the median of the upper half of the data. In this case, when the data is split, 5,5,6 represents the set of data in the upper half. Therefore the Upper Quartile would be 5. Because the data set is an even number, we landed on an exact value. If it was odd, we would take the average of the two center numbers.
Lower Quartile
The lower quartile is essentially the median of the lower half of the data. In this case, when the data is split, 1,2,3 represents the set of data in the lower half. Therefore the Lower Quartile would be 2. Because the data set is an even number, we landed on an exact value. If it was odd, we would take the average of the two center numbers.
Mean
The mean is visualized as the blue dot. It is the average of all the data points, in that it is the sum of the counts divided by the number of intervals. In our example, it would be (1+3+5+2+6+5)/6, or 3.66.
Minimum
The minimum value is as the name implies, the lowest count reached during the time frame. So in a report that trends per month, it would be the month where the technician had the least assigned. In our example data set, the value would be 1. This is indicated by the top 'whisker' on the graph.
As we can see from the graph above, this is a powerful tool as it provides context to the average performance. What was the individuals best and worst months? If the mean is above or below the median, it is usually because it is being pulled by the maximum/minimum.
The lower quartile and upper quartile represent the 25th and 75th percentiles of the individuals performance.
Is your organization utilizing trend box reports? Let me know in the comments below!
This blog is the second in a series explaining the value of non-conventional standard reports. See the first post on using control charts.
