These slides relate to the “Using Control Charts in a Healthcare Setting” case. This case was prepared by Professor Jack Boepple. Cases are developed solely as the basis for class discussion. Cases are not intended to serve as endorsements, sources of primary data, or illustrations of effective or ineffective management.

Introduction to Control Charts Supplement to “Using Control Charts in a Healthcare Setting” case

Variation Variety may be the “spice of life”, but in the context of product quality, process performance, & service delivery, variation is a BAD thing    Bears Fans Cheer! Bears Fans Groan! Bears Fans Groan! Career 187 made 218 attempts 85.8% success rate Customer Specification Limits Robbie Gould Image - http://www.nflfootballpicks.org/authors/6/Vic-Busey?Page=9 Robbie Gould Stats - http://www.nfl.com/player/robbiegould/2506264/careerstats Goal Post Image - http://www.partycheap.com/Jointed_Goal_Post_p/50474.htm

All Processes are Variable Special Cause Variation Unpredictable Intermittent Good Expected Variation Change Common Cause Variation Inherent Random New Expected Variation But the key is… Run Charts / Control Charts “We must understand variation.” W. Edwards Deming

Variation & Customer Specifications Expected Variation Customer Specs Expected Variation Customer Specs

One day, Tiger went to the driving range & hit the same way each time. Reacting to Variation Not satisfied with the results, he tried again the next day, but tried to improve each shot based upon the last one. One day, Tiger went to the driving range & hit the same way each time. What went wrong? Reacting the common case variation Tiger Woods Image #1 - http://moodfresher.blogspot.com/2012/02/tiger-woods-wallpapers.html Tiger Woods Image #2 - http://www.topnews.in/light/people/tiger-woods

Over-Reaction to Common Cause Variation? Examples An operator reacting in the opposite direction based on the previous result Reacting to a single customer complaint without understanding if it is common to many customers A manager reacting to a single data point Setting the current period’s sales quota based on last periods overage or underage Setting the next period’s budget as a percentage of the last period’s budget The stock market reacting to good news or bad news Unintended Consequences Existing workers training the new workers Symptom of no Standard Work (Lean concept) Over-reacting to Common Cause Variation leads to MORE variation, not less!

Understanding Variation Descriptive Statistics Average Percentage Median Range Visual Tools Histograms An approximation of the distribution’s shape Box Plots Scatter Diagrams Run Charts Control Charts SPC – Statistical Process Control

Run Charts Displays observed data in a time sequence So what? 3 different run charts with the same distribution 50, 5

Control Limits & Specification Limits are NOT the same Control Charts Run Charts w/Control limits Typically ± 3 standard deviations “Rules” for flagging special causes Customer Specs Expected Variation Customer Specs Originated by Walter Shewhart in mid-1920’s Will be using the data from Daily Tracking of your (a) Commute Time or (b) Weight Control Limits & Specification Limits are NOT the same

Some Control Chart Basics Typically, data is plotted as it happens However, a control chart can be created in an retrospective manner This approach requires some judgment when determining if there has been a process shift There are standard control chart tests (see next page) If one of these tests (or conditions) are violated, it is flagged  which is supposed to prompt an investigation as to “why” it happened

Control Chart Tests Numbers of the Line = Failed Test Test 1 Attribute 2 3 4 5 6 7 8 Attribute Tests Plus More Tests for Variable Data

Control Chart Selection Guide Source: Nancy R. Tague’s The Quality Toolbox, Second Edition, ASQ Quality Press, 2005.

Control Chart Selection Guide (another view)

More Control Chart Basics What they can do… Identify a process that is out-of-control Provide statistical evidence when a process has actually changed (either for better or for worse) What they cannot do… Identify why the process is out-of-control That is left for you to investigate

Never Stop Asking “Why?” Image - http://1.bp.blogspot.com/_IbpK-GhiWSc/TJTfX63zpVI/AAAAAAAACOI/na3ZgyUFd2M/s1600/1227573326bxGKsyD.jpg