Run Chart
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A run chart plots the points over time and adds an average line to the chart.  It is not a control chart as such but you can apply the rule of seven tests to the run chart.  An example of how to make a run chart is shown below.


Example


In this example, the dollar value of accounts receivable past due 90 days is being monitored.  We want to use a run chart to analyze the process.  The data collected is shown below.


1. Enter the data into a spreadsheet as shown below.


Week of

Accounts Receivable

2/5/2008

110

2/12/2008

104

2/19/2008

98

2/26/2008

112

3/4/2008

113

3/11/2008

100

3/18/2008

89

3/25/2008

113

4/1/2008

109

4/8/2008

105

4/15/2008

108

4/22/2008

95

4/29/2008

101

5/6/2008

98

5/13/2008

100

5/20/2008

105

5/27/2008

103

6/3/2008

99

6/10/2008

112

6/17/2008

98


2. Select the weeks  (the shaded area)



3. Select red variable control chart icon ( ) from the SPC menu and then the Run Chart option.


4. Fill out the Run Control Chart Input form.  The ranges are input at the top of the form; there are two pages on the form: Chart Names/Labels and Other Options.



a. Range Containing the Sample Identifiers: This is the range that contains the sample identifiers.  The default value is the first column in the range you selected prior to selecting the variable control chart option in the toolbar.

b. Range Containing the Data: This is the range containing the data.  The default range is the range next to the sample identifiers.


c. Chart Name/Labels Page

i. Name of Chart:  This name is the name that will be displayed on the worksheet tab.  It must be unique and meet the requirements for naming worksheets tab in Excel.

ii. Check for Trends: The option is selected if you want the program to check automatically for trends.  Default is false.

iii. Title: This is the title that goes on the l chart.  The default title is Run Chart.

iv. Y-Axis Label: This is the vertical axis label.  The default label is X.

v. X-Axis Label: This is the horizontal axis label.  The default label is Sample Number.

vi. Data in: Select columns or rows depending on how the data is entered into the spreadsheet.  The default depends on the range selected on the worksheet.

vii. Show Last N Points Only: Selecting this option will show only the last N points on the chart.


d. Other Options Page



i. Tests for Control: There is one option for interpreting the chart for control: the rules of seven (seven in a row above or below the average or trending up or down).  If an out of control situation is detected, the points on the chart will be in red.

ii. Automatic Updating of Average: Yes is the default which updates the average when new data is added to the chart; to prevent the average from changing, select the No option.

iii. Target for Average: This is the target value for the average.  It is not required.

iv. Print Average: There are two options.

1. On Average Line: This option prints the average value on the average line.  This is the default option.

2. In Chart Title: This option prints the value in the chart title.

v. Allow values below 0?: Sometimes, it is not possible for the variable to have values below 0.  If that is the case, select "No” for this option.  The default value is "Yes.”

vi. Dates of Data Collection: Add the starting date and ending dates of data collection.  These dates are optional.  If entered, the dates will be displayed in the lower left-hand corner of the chart.

vii. Generate New/Update Existing Capability Chart?  Select Yes to do a process capability analysis.  The default option is No.  See the Process Capability section in this manual for more information.

viii. Rounding to Use in Titles: This is the rounding to use for the average.  If the first cell in the range has been formatted, this format is used.  If not, the value entered here is used for rounding.  The program will estimate the rounding in the data.


5. Select OK and the run chart will be generated on a new chart sheet.  The run chart for this example is shown below.


Run charts can be updated when new data is added by selecting the Update Chart icon on the SPC Menu.  You may also change current options on the chart by selecting the Options icon from the SPC menu.  You can also split the average, start the chart at a new point, and add comments (see the Single Point Actions section in this manual)  or set the range to base the control limits on (see the All Points  Action section in  this manual).