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Domo Knowledge Base

SPC Charts - Beta

Version 4

 

Intro

SPC (statistical process control) charts, also known as control charts, Shewhart charts, or process-behavior charts, are line charts used to determine if a manufacturing or business process is in a state of control. Domo's SPC charts lets you set up rules from SPC standards by configuring them in the Chart Properties. When values outside the specified rules are encountered, these are flagged in the chart as outliers. 

Rules

There are 8 rules you can configure for SPC charts in Domo. You can have one SPC rule per chart or combine them. You configure rules for SPC charts in the Control Chart Rules menu in Chart Properties. For more information about these and other unique properties for these charts, see Properties for Data Science Charts

The rules you can configure are as follows:

Rule Description Example
Beyond Limits Points are flagged if they are outside of the automatically determined upper or lower limits of the chart, which are 3 standard deviations away from the mean. spc_rule1.png
2 of 3 Outside 2 Standard Deviations If 2 out of 3 consecutive points are outside of 2 standard deviations away from the mean, they are flagged. spc_rule2.png
4 of 5 Outside 1 Standard Deviation If 4 out of 5 consecutive points are outside of 1 standard deviation away from the mean, they are flagged. spc_rule3.png
Run Over/Under Mean If a specified number of consecutive points fall over or under the mean, they are flagged. spc_rule4.png
Trend If there is a specified number of consecutive points trending up or down, they are flagged. spc_rule5.png
8 Outside 1 Standard Deviation If there are 8 consecutive points outside of 1 standard deviation away from the mean, they are flagged. spc_rule6.png
15 Within 1 Standard Deviation If there are 15 consecutive points within 1 standard deviation away from the mean, they are flagged. spc_rule7.png
14 Alternating If there are 14 consecutive points that alternate up and down, they are flagged. spc_rule8.png

Powering SPC charts 

SPC charts are similar to basic line charts, requiring only two columns or rows of data from your DataSet—one for categories (generally dates or times) and one for values. For information about value, category, and series data, see Understanding Chart Data

In the Analyzer, you choose the columns containing the data for your Line graph. For more information about choosing data columns, see Applying DataSet Columns to Your Chart.

For more information about formatting charts in the Analyzer, see KPI Card Building Part 2: The Analyzer.

Customizing SPC charts 

You set the rules and customize the appearance of SPC charts by configuring their Chart Properties. For information about all chart properties, see Chart Properties. Unique properties of SPC charts include the following. You can click a thumbnail image to see a larger image. 

Property

Description

Example

General > Symbol Type

Lets you select the symbol used to denote points on the line (the default is a circle). In the example, the points appear as diamonds. 

spc_symbol_type.png

General > Line Thickness

Lets you determine whether the line in your SPC chart is thin (default), medium, or thick. In the example, the thickness has been set to thick.

spc_line_thickness.png

Control Chart Rules > Out of Control Color

Lets you specify the color of the outlier points as determined by your rules (the default color is red). In the example, the outlier color has been set to orange.

spc_out_of_control_color.png

Control Chart Rules > Beyond Limits

Turns on the "Beyond Limits" rule, which flags points if they are outside of the automatically determined upper or lower limits of the chart, which are 3 standard deviations away from the mean.

spc_rule1.png

Control Chart Rules > 2 of 3 Outside 2 Standard Deviations

Turns on the "2 of 3 Outside 2 Standard Deviations" rule, which looks at whether 2 out of 3 consecutive points are outside of 2 standard deviations away from the mean.

spc_rule2.png

Control Chart Rules > 4 of 5 Outside 1 Standard Deviation

Turns on the "4 of 5 Outside 1 Standard Deviation" rule, which looks at whether 4 out of 5 consecutive points are outside of 1 standard deviation away from the mean.

spc_rule3.png

Control Chart Rules > Run Over/Under Mean

Turns on the "Run Over/Under Mean" rule, which looks at whether a specified number of consecutive points fall over or under the mean. You specify the number of points that must be consecutive using the Color Chart Rules > Run Length option.

spc_rule4.png

Control Chart Rules > Run Length

Determines the number of points over or under the mean that must be consecutive for the "Run Over/Under Mean" rule to apply. 

Control Chart Rules > Trend

Turns on the "Trend" rule, which looks whether a specified number of points are trending up or down. You specify the number of points that must be consecutive using the Color Chart Rules > Trend Length option. 

spc_rule5.png

Control Chart Rules > Trend Length

Determines the number of points that must trend up or down for the "Trend" rule to apply.

Control Chart Rules > 8 Outside 1 Std Deviation

Turns on the "8 Outside 1 Std Deviation" rule, which looks at whether 8 consecutive points are outside of 1 standard deviation away from the mean.

spc_rule6.png

Control Chart Rules > 15 Within 1 Std Deviation

Turns on the "15 Within 1 Std Deviation" rule, which looks at whether 15 consecutive points fall within 1 standard deviation away from the mean.

spc_rule7.png

Control Chart Rules > 14 Alternating

Turns on the "14 Alternating" rule, which looks at whether 14 consecutive points alternately rise and fall.  

spc_rule8.png

Limit Lines > Mean Line Color

Determines the color of the mean line in your chart (the default is green). In the example, the mean line appears as purple.

spc_mean_line_color.png

Limit Lines > Mean Line Style

Determines the style of the mean line in your chart, whether solid (default), dotted, or dashed. In the example, the mean line appears solid. 

spc_mean_line_style.png

Limit Lines > Upper/Lower Control Line Color

Determines the color of the upper and lower limit lines (the default is red). In the example, the limit lines appear as orange.

spc_upper_lower_lines_color.png

Limit Lines > Upper/Lower Control Line Style

Determines the style of the upper and lower limit lines (the default is dashed). In the example, the limit lines appear dotted. 

spc_upper_lower_lines_style.png

Limit Lines > Show 1-2 Std Deviation Lines

Determines whether standard deviation lines appear in your chart. When these are present, they appear as green and dotted.

Limit Lines > 1st Std Deviation Line Color

Determines the color of the 1st standard deviation lines in the chart (the default is green). In the example, the lines appear as purple.

spc_1st_std_deviation_color.png

Limit Lines > 1st Standard Deviation Line Style

Determines the style of the 1st standard deviation lines in the chart (the default is dotted). In the example, the lines appear solid and red.

spc_1st_std_deviation_style.png

Limit Lines > 2nd Standard Deviation Color

Determines the color of the 2nd standard deviation lines in the chart (the default is green). In the example, the lines appear as purple.

spc_2nd_std_deviation_color.png

Limit Lines > 2nd Standard Deviation Style

Determines the style of the 2nd standard deviation lines (the default is dotted). In the example, the lines appear as red and solid.  

spc_2nd_std_deviation_style.png