What is Trend chart?
Trend chart also known as run graphs, trend charts are used to demonstrate information trends over time. All procedures differ, so measurements of single points can be inaccurate.
Trend analysis is a mathematical method used to forecast future outcomes using historical outcomes. This is accomplished by monitoring parameter variances
Displaying information over time improves knowledge of a process’s actual performance, especially when it comes to an established objective or target.
A trend chart:
Characteristics of Trend chart:
Labels on the vertical Y-axis and the horizontal X-axis to describe the time and measurement.
A legend to distinguish the lines plotted the actual vs. the objective in this situation
Suitable scales that are sufficiently small to demonstrate variation
Limited features on each graph to prevent too many lines of confusion.
An appropriate time frame.
Notations on any major spikes
Targets or goals should be noted on the chart for reference
Note who prepared the chart in case there are questions about the chart or the data.
Common errors in chart examples:
The figure graph has a scale that is so broad that it is possible to see little variety. The information is right, but the graph is not very helpful as the scale is so broad (0-100%).
The graph below has a scale that contains impossible figures based on the plotted metric definition. In this case, the fill rate can not be greater than 100%, so it is misleading to have a scale that goes up to 110%.
A third issue is the use of long time scales and inappropriate plots of the trend line. Sometimes for a long-term view, this practice is useful, but it can be confusing if it diverts attention from more latest events, especially when a trend line is plotted through the information. Shown below: