How to create c- or u-chart
This help page describes how you can create c- or u-chart in Power BI, using the Craydec Control Charts.
What are they / When to use
The c- and u-charts are used to track the number of faults in items produced by a process over time. Both charts use count data, for example number of defects in inspected items. Interpreting the count requires an Area of Opportunity, for example, number of parts produced.
The c- and c-charts track number of defects. This means that item can have multiple defects.
The difference between the c- and u-chart is that c-chart has fixed Area of Opportunity, and u-chart has variable AoO.
The Area of Opportunity is variable in u-chart, creating different limits for each data point.
Creating c-chart
Data required
x, count
Example data. This data is used in the downloadable example report.
id = x, number_faulty_items = measured value
Steps
1) Add visual to the report
See the Microsoft’s documentation.
2) Prepare data
See the Microsoft’s documentation.
Note that count must be numeric data type, usually a whole number. 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.
3) Add data roles
Select data roles. As order of the data lines is important 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 > ‘u-chart’. You have to have a valid license to change the chart type.
6) Check results
Common errors
See separate common errors page.
Examples
See the example report. Data contains fictional set of count of defects in items produced by a process.
Creating u-chart
Data required
x, count, area of opportunity
Example data. This data is used in the downloadable example report.
id = x, number_faulty_items = measured value, area_of_opportunity = Area of Opportunity
Steps
1) Add visual to the report
See separate help page.
2) Prepare data
See separate help page.
Note that count and area of opportunity must be numeric data type, usually a whole number. 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.
3) Add data roles
Select data roles. As order of the data lines is important 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 > ‘u-chart’. You have to have a valid license to change the chart type.
6) Check results
Note that u-chart must relate the count to the area of opportunity, so the result is shown as rate. This is a feature of a u-chart, and it cannot be avoided.
Common errors
See separate common errors page.
Examples
See the example report. Data contains fictional set of count of defects in items produced by a process.