Control Chart XmR
על-ידי Nova Silva
The most effective way to detect signals of change in your KPI is to use a Control Chart (XmR chart)
The Control Chart XmR helps you to determine if your processes are in control. When your measurements meet certain criteria (see below), an indicator immediately tells you something is going on. This helps you to determine the source of this variation.
The Control Chart XmR consists of two charts: The upper chart (X-Chart) displays the data points over time together with a calculated average. The calculated average is then used to calculate the Upper and Lower Control Limits (UCL and LCL). The lower chart displays the Moving Range (mR-Chart) with its Average and Upper Control Limit. The mR-Chart can be hidden.
The rule set for the detection of signals is customisable. By default it is:
- A point is outside the control limits
- 7 points in a row are above or below the center line
- 10 out of 12 points are above or below the center line
- 3 out of 4 points are closer to the UCL or LCL than the center line
Besides these rules (known as the Wheeler Rules) you can also apply the Nelson Rules. These detect signals in the following situations:
- One point is more than 3 standard deviations from the mean;
- Nine (or more) points in a row are on the same side of the mean;
- Six (or more) points in a row are continually increasing (or decreasing);
- Fourteen (or more) points in a row alternate in direction, increasing then decreasing;
- Two (or three) out of three points in a row are more than 2 standard deviations from the mean in the same direction;
- Four (or five) out of five points in a row are more than 1 standard deviation from the mean in the same direction;
- Fifteen points in a row are all within 1 standard deviation of the mean on either side of the mean;
- Eight points in a row exist, but none within 1 standard deviation of the mean, and the points are in both directions from the mean.
The visual can be set to only detect these signals, and can optionally recalculate the central line and corresponding control limits.
Key features of the Control Chart XmR are:
- Switch between standard and trending XmR: processes with natural trends (continuously increasing or decreasing) can be analysed with the Trending XmR function;
- Highlight signals: Detected signals can be indicated below the chart, and the measurements themselves can be coloured in a separate colour;
- Work on various time scales: choose the appropriate time scale for optimal analysis, ranging from seconds to years;
- Format the objects: All lines, markers and axes can be formatted independently, and support theme settings;
- Selection & Highlighting: Like in standard Power BI Charts you can make use of the Selection & Highlighting functions within the Control Chart XmR;
- Context menu: Like in standard Power BI Charts you have access to the context menu to include and exclude data points;
- Full tooltip support: Besides the default Tooltip behaviour (show the value of the element you hover) you can also add additional fields to the tooltip.
- Full Bookmark support: like any of the standard visuals the Control Chart XmR supports Bookmarks.
This visual offers in-app purchases and comes with free access to evaluate the paid features.
All functionality of the Control Chart XmR is available for free within Power BI Desktop. The licensed version is needed for sharing the reports with your colleagues in Power BI Service. Need more information? Visit our site at: https://visuals.novasilva.com
This visual is compatible with Power BI Desktop May 2020 and newer
