Chapter 16 Flashcards
Root cause analysis
four step method called root cause corrective analysis (RCCA)
en effective method for identifying and addressing root causes of sporadic problems and processes
The four basic steps of RCCA
Identify a problem
Diagnose the cause
Remedy the cause
Hold the gains
Methods for root cause analysis
Plan-Do-Study-Act (PDSA) cycle
Plan-Do-Check-Act (PDCA) cycle
Just do it
When to use PDSA and PDCA methods?
useful methods for root cause analysis, planning and executing tests of potentially beneficial changes
When to use Just Do It method?
Useful approach when the need to solve a problem is urgent, penalties for risks of failed ‘solutions’ are low, rewards of effective solutions are high
Purpose of RCA
to solve problems that occur due to special or assignable causes
sporadic problems - happen periodically
Methods to discover root causes
Six sigma DMAIC
Juran’s breakthrough model
RCCA
PDCA
Lean problem-solving
PDSA
Just do it
Control
restoring process performance to previously acceptable level
- deals with special causes
Improvement
changing the very nature of the process, creating breakthrough, moving to new/better level of performance with reduced waste and COPQ
- deals with common causes
To ensure all processes are in a state of control requires three basic elements
- Means to know actual performance of process
- Ability to compare actual performance to targets/quality goals
- Means to act on difference to maintain control (method to determine what correct actions should be taken)
PDCA
Plan, Do, Check, Act
a means to set up control functions
Juran’s RCCA method
Root cause corrective action
a simple method needed to solve daily, sporadic small-scope problems
1. identify a problem
2. Diagnose the cause
3. Remedy the cause
4. Hold the gains
Identify a problem: sub-steps
Is the problem sporadic?
Establish responsibility to solve it
Prepare problem statement
Diagnose the cause: sub-steps
Analyse symptoms
Formulate theories
Test theories
Identify root causes
Remedy the cause: Sub-steps
Design and implement the remedy
Hold the gains: sub-steps
Adjust controls
Tools used for RCCA
Affinity method
Brainstorming
Cause-and-effect diagrams
Data collection methods
Failure mode and effects analysis (FMEA)
Graphs, charts
Expected outcomes of Root Cause Analysis
Primary output: uncover the root causes of the problem
- Identify weaknesses/other contributing factors
- Better understand the process surrounding the problem as well as supporting processes
- Create an architecture into which you can build your corrective action plan
PDSA
Plan, Do, Study, Act
Primarily a guide for identifying root causes through experimentation
Iterative experiments performed to identify root causes
Seeks to confirm/refute ideas of problem causes by trial and error of solutions
PDSA steps
- Plan
- define change to be tested
- design experiments to test change - Do
- carry out experimental plan
- collect data about effectiveness of change - Study
- analyse data from experiment
- summarise what was learnt - Act
- determine what permanent changes to be implemented
- determine what additional changes need to be tested
Advantages of PDSA
Yield results quickly if experiments are good at selecting solutions that will yield true improvement
Follows experimental approach - yields a great deal of useful knowledge
Widely accepted
Disadvantages of PDSA
Can be slow if experiments aren’t good at selecting solutions that will yield true improvements
Changes that don’t succeed may not yield a lot of useful information
Experimentation can be disruptive and resource intensive
Experimentation can be costly
Just Do It (JDI)
no root cause analysis involved as root cause is readily apparent
analysing root cause is done entirely by observation
To implement JDIs, 3 factors must be present
1) need for change must be urgent
2) change must carry a low cost of failure
3) change must have a significant potential reward
