How to create I- or ImR-chart
This help page describes how you can create I- or ImR-chart in Power BI, using the Craydec Control Charts.
What are they / When to use
The I-chart is the workhorse of the control charts. It can be used almost in every situation than the more specialized charts. It also does not require the data follow any distribution, as it uses the data itself to determine the limits.
If you are uncertain which chart to use, start with I-chart.
The difference between I- and ImR-chart is that ImR-chart shows also the change in variation. Is some situation, for example when change is fast but the values are inside the limits, the variation chart can help to spot the anomaly.
ImR-chart shows also the change in variation.
Creating the chart
Data required
x, measured value
Example data. This data is used in the downloadable example report.
Data roles:
id = x, value = measured value
Steps
1) Add visual to the report
See the Microsoft’s documentation.
2) Prepare data
See the Microsoft’s documentation.
Note that measured valued must be numeric data type. X can be number, text, or date, but it must sort the data correctly. It is also good idea to have unique values for x in each row, unless ‘Row ID’ is used.
Take special care to make sure that your data is in correct order in visualization, as it has dramatic effect on the limits. Usually it is correct to sort the data by time.
3) Add data roles
Select data roles. As the order of the data is crucial for the correct visualization, it is safest to start by selecting ‘id’ or ‘x’ data role first.
4) Enter a license code
See the help video.
5) Change chart type
Select Format > Chart > Chart Type > ‘I-chart’ or ‘ImR-chart’, depending on which chart you want to create. You have to have a valid license to change the chart type.
6) Check the results
Look at the results and check if they are plausable. Also make sure the data is in correct order.
If you are unsure, try to recreate some of our example reports to gain confidence.
Common errors
See separate common errors page.
Examples
See the example report. Example contains a data set which can be used to create an I or ImR-chart.