Statistical Process Improvement
Georgetown University
 

Tukey Chart


 

This topic continues to examine control charts that require only 1 observation per time period.  These include time-between and Tukey control charts. This section focuses on Tukey chart. 

Assigned Reading

  • Introduction (use instructor's last name as password) Read►

Presentations

Assignments

Instruction for Submission of Assignments: Assignments should be submitted directly on Blackboard.  In rare situations assignments can be sent directly by email to the instructor. Submission should follow these rules:

  1.  Submit only one document, usually an Excel file.  All questions should be answered in different sheets.  Each sheet should be labeled with the question number. 
  2. All Excel cells, except the cells containing the data, must have formulas.  Do not paste the value into the cell, it must be calculated using a formula.  Even simple steps, such as adding two numbers, should be done using formulas. 
  3. Make sure that any control charts follow the visual rules below:  (1) Control limits must be in red and without markers, (2) Observed lines must have markers, (3) X and Y axis must be labeled, and (4) Charts must be linked to the data. 
  4. Copy and paste SQL or R code into Excel sheet.  Plot data in Excel. 
  5. The first sheet in the file should be a summary page.  In the summary page you should list how your answers to the question differs from answers provided within the assignment (inside Teach One or other answers).  You must indicate for each question if your control chart is exactly the same as seen in Teach One or other formats.  For each question, you must indicate if the answers you have provided is the same as the answers supplied on the web.  If there are no answers provided, you must indicate that there were no answers available on the web to compare your answers to.

Question 1: In health administration programs, data on waiting time are examined in courses on quality and operations research.  Using the attached data, determine if the waiting time in our urgent care center has changed? Data► Answer►

Question 2: In Hospital Administration Programs, time to adverse events is typically taught in courses on quality.  It also may be referred to in courses on strategy, if the hospital is focused on competing based on quality.

Hospital Compare reports the measure OP_21. The Score field provides time (in minutes) from emergency department arrival to initial oral, intranasal or parenteral pain medication administration for the patients with a diagnosis of a long bone fracture.  The field Sample provides the number of patients used to calculate the time to pain medication. In this assignment, we ask you to track the performance of "Inova Fairfax Medical Center" over two years. Focus on the Score variable.  Download Hospital Compare data; these years include data from 2013 to 2015.  Merge the file " HQI_HOSP_TimelyEffectiveCare" across all the databases that you have downloaded.  Select measure ID: "OP_21" .  Construct a control chart showing time between pain medications. The data are reported for a range of time; assume that the data are reported for the mid-point of the range. Download data using the following 9 files:  Rationale 2016-11-10.zip► 2016-08-10.zip► 2016-05-04.zip► 2015-12-10.zip► 2015-10-08.zip► 2015-07-16.zip► 2015-05-06.zip► 2015-04-16.zip► 2015-01-22.zip►

Construct both a Tukey and a time-between control chart for the data.   For the time-between control chart assume that data points above median exceed and observations below median are less than the national average. Answer►

Question 3: Analyze the following data using Tukey, XmR and Time-In-Between (more than 30 minutes of exercise considered a successful day) charts. Produce 3 charts and discuss if the findings from the 3 charts are similar.  To decide if the exercise time has changed, rely on the control chart with the smallest difference between upper and control limit. Data► Answer►

Question 4: Analyze "Death rate for CABG surgery patients", this is measure code MORT_30_CABG. Choose George Washington University Hospital.  Choose for its competitors Medstar Washington, VHC, and INNOVA Fairfax. You will find this measure inside "Complications and Deaths - Hospital" file.  The measure was named this way in the year 2018. Include all years of data. The denominator reports the number of cases.  The numerator reports the risk-adjusted mortality rate. Note that the name of the file may change in different years but the measure code remains the same. Compare the performance of the hospital to the competing hospitals in its market, including Medstar Washington, INOVA Fairfax, and Virginia Hospital Center. Draw the observed rate at GWU.  The control limits should come from the experiences of its competitors, which is a weighted average of each of the competitor.  Data► Answer►

 

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Copyright 1996 Farrokh Alemi, Ph.D. Most recent revision 12/17/2019.  This page is part of the course on Statistical Process Improvement.