t Chart in Excel

Use a t Chart to analyze the time between rare events

The t Chart is used to evaluate process stability when analyzing the time between rare events. For example, never events in healthcare such as retained foreign objects during surgery. (See QI Macros Test Data/healthcare spc.xlsx).

t Chart example created by QI Macros for Excel

t chart in excel

To create a t Chart in Excel using QI Macros:

  1. Just click and drag over the data to select it.
  2. Then click on the QI Macros menu, Control Charts > Attribute, then t Chart.

    attribute control charts
  3. QI Macros will do all the math and draw the t Chart for you. QI Macros will also turn any unstable points or conditions on the t Chart red. These should be investigated.

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