The term population refers to all of the measurements of interest. For example, if you were trying to find the average weight of United Airline passengers flying from San Francisco to Hong Kong for the month of March, the population would include all of the weights for all of the passengers who flew from San Francisco to Hong Kong for the month of March via United Airlines.
Pre-control is a control charting methodology that uses specification limits instead of statistically-derived control limits to determine process capability over time.
Pre-control charting is useful in initial process setup to get a rough idea of process capability, but this author doesn’t recommend its use because it is not statistical process control. Pre-control charting does not use continuous data found upstream in the process which is more in alignment with prevention thinking.
A prioritization matrix is typically an L-shaped matrix that makes pair-wise comparisons of established criteria and options. The prioritization matrix is a rigorous method and requires skill to use it effectively.
It is applicable to many situations and has several different configurations. To be used effectively, the criteria and the options must be clearly developed and a scheme for weighing them must be applied.
Probability deals with calculating the likelihood of a given event’s occurrence.
If you are using a Standard Normal Table to determine the probability of a given Z value will yield some probability from 0 to 1 of a particular data point being either above, or below a certain point. For example, if hospital stays for admitted patients at a certain hospital are measured in hours and were found to be normally distributed with some average hours and some standard deviation; maybe the team would want to find out how many stays can be expected to last over so many hours. Or, it could be expectations for being less than so many hours.
You would be using probability if you are using a Weibull analysis to determine the probability of something lasting so many years, or so many miles.
Probability theory is used with binomial data where the team might be trying to find the probability of a specific number of ‘successes’.
A Process Decision Program Chart (PDPC) is a tool for identifying and documenting the steps required to complete a process.
It is useful for anticipating any issues and problems that might surface in the implementation of the process, therefore affording the opportunity to devise countermeasures.
Quality Control is the control of the operational techniques and the activities used to fulfill requirements of quality. One way to control quality of a product or service is to provide in-process and/or final inspection. The problem with inspection is that experts maintain that even with 100% inspection, inspection is only 80% effective – at best.
There are many definitions of quality. Some define quality as ‘conformance to requirements’. Others define quality as merely ‘meeting-the-customers’ specifications’. When the mentality is to focus on the most marginally-accepted product or service (focusing on either the upper or the lower specification, or both), it isn’t as competitive as focusing on the most ideal product target. This author defines quality as: Product uniformity around a target value(s). The target might be a larger-is-better quality characteristic or a smaller-is-better quality characteristic. It might also be a nominal-is-best where some named value is the target. With any of these quality characteristics, it is important that there is relentless attention paid to having as little variation around the target values as possible, or competitive.
A Pull System is a control-oriented system that operates by receiving signals that more production is needed. A pull system is contrasted with a typical push system that is common with mass production.
In a pull system, the requirement to produce more occurs as a ‘signal’ from one process to the previous process. This is counter to the way a lot of processes operate.
Project management is the discipline of Initiating, Planning, Executing, Monitoring and Controlling, and Closing projects to achieve specific goals. The Work Breakdown Structure is at the heart of .
The Work Breakdown Structure breaks down the project into smaller components. It defines and groups a project’s work elements in a way that helps organize and define the total work scope of the project.
A process owner is fairly self-explanatory, but many times in lean six sigma, the process owner is not identified until the ‘ideal process state’ has been put into place.
The importance of the process owner reveals itself in the last two subtasks of the control phase of DMAIC. The process which is usually somewhat of a new process needs to be managed by one person who will ensure that the improvements are sustained. Without a process owner, it is only human nature that a process will tend to go back to the old way.
