Statistics for the Healthcare Quality Professional Susan Mellott PhD, RN, CPHQ, FNAHQ Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Objectives Use basic statistical techniques to describe data and to evaluate data Use or coordinate the use of statistical process control components Use or Coordinate the use of process analysis tools to display data Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Mom Baseball Statistics Apple Pie Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com What Type of Data? The type of data that you have controls what tools, statistics and display format are utilized Everything is driven from this Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Type of Data Measured Data Time, Volume, Money, Scores Run Chart Control Chart Mean, Median, Mode, Range T-test Category – Count Data Categories or groups Histogram Percentage Chi Squared Mellott & Associates LLC www.mellottandassociates.com

Categorical Data Examples Men vs Women Age Ranges (0-30, 31-50, 51-70, 71+) DRGs Types of falls Types of injuries Diagnosis Complications Mellott & Associates LLC www.mellottandassociates.com

Measured Data Examples Temperature LOS Average daily census Scores on a test Pre and Post Test scores Anything over time Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com In Healthcare Quality Use more measured data than categorical data, but there is a place for each Use more Run and Control charts than Histograms Mellott & Associates LLC www.mellottandassociates.com

And then there are other Problem Solving Tools Cause & effect diagram Pareto diagram Scatter diagram Regression analysis Mellott & Associates LLC www.mellottandassociates.com

But First…… Some Basics Mellott & Associates LLC www.mellottandassociates.com

Reliability and Validity The ability to get the same answer time and time again if nothing changes Validity To be sure you are counting or measuring what you intended to count or measure Mellott & Associates LLC www.mellottandassociates.com

Reliability and Validity Must have reliability before you can have validity HINT: R comes before V in the alphabet Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Reliability Test / Retest reliability Inter-Rater reliability *** Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Validity Face Validity Lowest level Criterion Validity *** Based on criteria Construct Validity Hardest to obtain Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Sampling How you pick your sample influences what you can do with your results Can you generalize the findings outside of the sample you used Are you confined to use your findings only in relation to the sample itself Probability vs Non-Probability Usually use of combination of each type Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Probability Sampling You probably will be able to generalize your findings Simple Random All items have an equal chance of being chosen Stratified Random Creating 2 or more homogeneous groups and then randomly selecting items Men vs Women Systemic Random Every n’th case Mellott & Associates LLC www.mellottandassociates.com

Non-Probability Sampling You probably will not be able to generalize your findings Convenience Using data readily available Quota Set number of data sets Purposive Demonstrate a desired characteristic Expert sampling Men vs Women Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Data Collection Must assure that measuring what you intend to measure Pre-test your data collection tool! Verify collection questions with requestor of the data Must assure that all data collectors collect the data from the same places and in the same manner Mellott & Associates LLC www.mellottandassociates.com

Before Collect Data, Must: Know how you want to manipulate data; Know how you want to display data; Know how you want to report data; All of which is based on type of data! Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Categorical Data AKA: Attribute, Qualitative, Nominal, Ordinal, Discrete Examples: # of members, patients, births, procedures, occurrences, gender, ethnicity Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Categorical Data Usually Reported as: % in each category, whole numbers Usually Displayed as: Histogram, pie chart Usual statistical test of difference between groups: Chi Squared Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Measured Data AKA: Continuous, Variable, Quantitative Examples: Age, height, weight, temperature, time, charges, LOS Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Measured Data Usually Reported as: Mean, median, mode, minimum, maximum, percentiles, whole and fractional numbers Usually displayed as: Run charts, control charts Usual statistical test of difference between groups: T-test, or in special cases a Z-test Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Mean, Median, Mode Mean: Average Can be influenced by outliers/extreme values Median: Middle of data Best utilized when there are outliers Mode: Most frequently occurring numbers Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Examples 2, 4, 6, 8, 10 Mean: Median: 2, 4, 6, 8, 100 Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Example 2, 4, 6, 7, 8, 10 Mean: Median: 0, 0, 0, 0, 0, 7, 12, 26 Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Examples 2, 4, 6, 8, 10 Mode: 2, 3, 3, 4, 6, 8, 10 2, 3, 3, 4, 4, 4, 6, 8, 10 Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com STANDARD DEVIATION Mellott & Associates LLC www.mellottandassociates.com

Statistical Differences between Groups Clinical differences occur before statistical differences Categorical data – Chi Square Measured data – T-test Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Chi-Squared test Similar to a t-test Get an X2 value Then look that value up on a p-value table like a t-test score Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com T-test Reported as a ‘p’ score Ranges from 0 to 1 0.05 and less shows statistical differences 1 0.25 0.5 0.05 Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Histogram (Bar Chart) What is it: A display of comparisons between different categories or groups When used: To look at differences between categories or groups (non-statistical differences) What it will tell you: What the amount of differences look like Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Histogram vs Run Chart vs Control Chart only with categorical data Best to display one to three points in time If more than three points in time, better to use run chart Much more effective than a pie chart Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Run Chart (Line Graph) What is it: A line graph display of performance changes over time When used: To look at data over time What it will tell you: What is baseline performance? Amount and type of variation in a process? Is process changing over time? Is change an improvement? Mellott & Associates LLC www.mellottandassociates.com

Histogram vs Run Chart vs Control Chart Categorical data over time Sequential Data points Display comparison between years, hospital units, stratification of data Prior to having enough data for Control Chart Mellott & Associates LLC www.mellottandassociates.com

Control Chart (Line Graph) What is it: A line graph display that compares actual performance to the mean and includes upper and lower control limits When used: To display normal variations and out-of-control variations What it will tell you: Common cause or special cause variation Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Control Chart Conceptually – Run chart with standard deviation curve placed on its side Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Control Charts Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

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Mellott & Associates LLC www.mellottandassociates.com Regression Analysis Simple Regression How one variable affects another variable Example: number of calories eaten vs weight gain Multiple Regression How multiple variables affect another variable Factors related to compliance with medication regime Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Regression Analysis Scatter Diagram Pictorial representation of a simple regression Positive Relationship Data goes upward in an oval shape Negative Relationship Data goes downward in an oval shape No relationship Data neither goes upward nor downward Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Positive Correlation Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Negative Correlation Mellott & Associates LLC www.mellottandassociates.com

No Relationship or Correlation Mellott & Associates LLC www.mellottandassociates.com

Multiple Regression in Health Care Quality Many examples where multiple regression could be an important tool: Factors related to compliance with medication regime Factors related to infections Factors related to high cholesterol Factors related to flexibility & strength Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Multiple Regression Pareto diagram Cause & Effect diagram Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Pareto Diagram What is it: Pictorial representation similar to multiple regression When used: When you want to determine where to start to get the biggest ‘bang for your buck’ What it will tell you: Where you should start in your improvement efforts Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Cause & Effect Diagram What is it: Pictorial representation similar to multiple regression When used: When you want to determine where to start to get the biggest ‘bang for your buck’ What it will tell you: Where you should start in your improvement efforts Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Cause & Effect Use when “bad” things happen to determine how it happened Use when want “Good” results to determine what you need to do to get those results Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Cause & Effect Diagram Effect Cause Mellott & Associates LLC www.mellottandassociates.com

Mellott & Associates LLC www.mellottandassociates.com Showplace of Medical Readiness Life Quality Improvement NTC Surgeon Time Community Wellness PAT Measurement Leadership Resources Wellness Focus Summer Turnover MASCAL/EPP Lack of Measurement Info Technology Youth Info Technology Community In-processing Soldier Assist Board NCO Corps Awards Program DRETS AMMED Council PT Test FSG Oasis of Care FSG Focus Focus Management Orientation Access Info Flow Info Technology Turnover Team Work Staffing Restraints Committed Staff EC Issues Customer Focus Lack of Measurement MC/CS Division Ambulatory Care Center Commitment to Vision Isolation Shallow Staffing Limited Access to Specialists Master Calendar Speed of Change Mentor Program Medical Records Soldier Assistance Board Admin CBO Info Technology Library Empowered Staff Clinical CBO Education Program CME OPD NCOPD SGT’s Time This is an example of using a Cause and Effect diagram as an annual organizational assessment. This is from Weed Army Community Hospital at Fort Irwin, California. It is at the National Training Center in the Mojave Desert. Their vision is to be an OASIS of CARE. The Four components of that vision are at the 4 corners of the drawing. The right side of the lines are their strengths and the left are their weaknesses (in red). World Class Service Professional Excellence Mellott & Associates LLC www.mellottandassociates.com © M. Ellicott

Mellott & Associates LLC www.mellottandassociates.com Summary You first need to know what kind of data you are working with Then you have to know the types of tools and statistics you can use with that kind of data Then you design the data collection and plan the analysis of that data Mellott & Associates LLC www.mellottandassociates.com