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Run Charts
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The Importance of Data within the BTS
Each team will have theories on why they have problems within their sites, the collection of data and its analysis assists these teams with discovering answers to their hypotheses. If we can’t measure something we have no way of improving it. Measuring your data points over time will help you identify areas within your project that need more focus You can then identify specific areas of need without spending extended time and effort with the whole project
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What is a Run Chart
Run charts are used to understand the trends and shifts in a process or variation over time, to identify decline or improvement in a process over time
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Why a Run Chart? Process change happens over time Determining if a change has happened, and if that change lasts overtime is important to process improvement A run chart will help study observed data for trends or patterns over a specific period of time and focus attention on vital changes in the process The run chart is useful for tracking information and predicting trends or patterns
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Static vs Dynamic View of Data
Courtesy: IHI
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Static vs. Dynamic Interpretation
Change implemented
Cycle time (min)
Change implemented
7 Key Resource: Moen et al Quality Improvement through Planned Experimentation 1999
Static vs Dynamic Dynamic View View UCL
LCL
Every process displays variation • Common Cause/ Statistical Variation – Stable, consistent patterns of variation, “chance”, constant causes Static View • Special Cause Variation – assignable, pattern changes over time, non-random
8 Chad Glenn, Innovation Group
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How many data points?
• Typically you should have between 15 – 20 data points before constructing a chart . 15 – 20 patients . 15 – 20 days . 15 – 20 weeks . 15 – 20 months . 15 - 20 quarters…?
9 Courtesy: IHI
Elements of a Run Chart
Data Point
Four simple run rules are used to determine if special cause variation is present
10 Courtesy: IHI
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Rules to Identify non-random patterns (Special Cause Variation) in the data displayed on a Run Chart
Rule #1: A shift in the process, or too many data points in a run (6 or more consecutive points above or below the median)
Rule #2: A trend (5 or more consecutive points all increasing or decreasing)
Rule #3: Too many or too few runs (use a table to determine this one)
Rule #4: An “astronomical” data point
11 Courtesy: IHI
Rule 1: Shift
Courtesy: IHI
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Rule 2: Trend
Courtesy: IHI
Rule 3: Number of Runs
Courtesy: IHI
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Rule 4: Astronomical Data Point
Courtesy: IHI
Making sense of the data is a process
Data Analysis Interpretation
Input Transformation Output
“This shift in data points seems to indicate that the underlying process has undergone some kind of change…”
Key Resource: Donald Wheeler Understanding Variation/ Managing Chaos 1993
16 Chad Glenn, Innovation Group
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Important Uses of Run Charts for Improvement Activities
Display data over time to make process performance visible
Determine whether a change led to an improvement
Determine if gains are held after a change has been implemented
17 Chad Glenn, Innovation Group Courtesy: IHI
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