Dictionary of Lean Six Sigma Tools/Concepts
There are 19 entries in this dictionary.| Term | Definition |
|---|---|
| P Chart | A statistical control chart that uses a binomial distribution to measure the proportion of defects in a sample. It is primarily intended for evaluating discrete (a.k.a. attribute or categorical) values. |
| Paired T Test | A test used to measure the statistical difference between the means (a.k.a. average) of two continuous (a.k.a. variable or numerical) values. This test is best for dependent variables that are sampled from the same group (e.g., measurements from the same machine before and after a system upgrade, or performance metrics from the same call center before and after process changes, or sales metrics from teh same store before and after new training, etc.). It is generally used when the distribution for the continuous value is normal, hence the use of the mean. When the distribution is non-normal, the mean may not be valid so the median would be a better measure for central tendency; in those cases, try the Mann-Whitney Test. For data having independent variables, use a Two Sample Test. |
| Pearson Correlation | |
| Performance Objectives | The goal(s) set for improving a process. It can be set based on the performance gap (the difference between the Voice of the Customer or VOC and the Voice of the Process or VOP). |
| PICK Chart | See Impact Matrix |
| Pilot Plan | |
| Piloting Solutions | Testing the improvement(s) that the team brainstormed and expected will solve the original problem of the project. Conducting a pilot of the solution is usually done on a smaller scale from a full implementation in order to validate the improvements and ensure a smooth implementation. |
| Plus/Delta Tool | A tool used in a group meetings to help get feedback about the meeting or a project. It involves drawing two columns where one represents the positive feedback (what the group thinks went well) and the other represents the negative feedback (what the group thinks didn't go well and needs improvement). |
| Poka Yoke | A Japanese term meaning "mistake proofing", it refers to steps, controls, or mechanisms designed to prevent mistakes (potential defects). It implies a method in the process that quickly and easily detects, fixes, and prevents errors as they occur. |
| Population Data | Data that represents every possible observation from its data source. It is ideal but very rare to get and often unnecessary. This can be contrasted with Sample Data. |
| Ppk | A measurement of the long-term process performance (a.k.a. voice of the process or VOP) in relation to the spread (or total tolerance) between the customer's lower/upper specification limits (LSL/USL) (a.k.a. the voice of the customer or VOC). It's used for measuring process capability where if it's less than 1, then the process is not capable within the LSL/USL tolerance. The higher it is above 1, the more capable the process is of achieving results within tolerance. It is calculated as the minimum(Zusl/3, Zlsl/3). Since it represents long-term data, it will always be lower than Cpk (which represents short-term data); if it's significantly lower than Cpk, then it's likely driven by the long term variation (mean shift) between sub-groups. |
| Probability Plot | See Normality Test |
| Problem Statement | A clear and succinct description of the problem being solved by the project. It's intended to briefly define the symptoms behind the critical pain-point(s) in the business, to validate the need of the project, and to remind and unify the team around why they are part of the project. |
| Process Capability | |
| Process Maps | A visual diagram of the flow of an entire process across critical steps and decision points. It can be reflected at a high-level or detailed level that should be determined by the team. It can reflect just one sub-process or can inter-connect multiple sub-processes. |
| Process Owner | An external resource in a project that falls under the Champion role, it's usually the role given to lower-level management like a team lead, supervisor, manager, or higher. They have direct ownership and responsibility for the process targeted by the project and often serve to drive coordination for getting resources and either removing roadblocks or escalating them to the Champion. Communication with them by the LSS project leader tends to be very frequent (i.e., about 1 to 2 times per week). |
| Project Charter | A document (typically one page) that summarizes the critical answers to the questions for the Define phase of Six Sigma's DMAIC methodology. It's purpose is to validate the need for the project and the team who will be leading it in order to acquire and sustain Sponsor approval for the project. There is no standard format nor any standard elements included on the charter. However, the most commonly used elements include a Problem Statement, Project Scope, and a list of team members. It can also include other helpful elements such as a Background Statement, a pre-assessment of benefits, CTQ Drilldown, project strategy, etc. |
| Project Methodology Decision Tree | A drilldown visually depicting the decision process for finding the right methodology and project type for solving a problem. It narrows down the focus of a project for whether is should have a focus on improving efficiency using Six Sigma's DMADV or Lean approaches, or a focus on improving effectiveness using Six Sigma's DFSS or DMAIC methodologies. |
| Push vs. Pull System | From a customer's perspective, it describes how they get an item from upstream in a process flow. In a push system, the upstream processes pushes items downstream without balancing to the customer's demand. In a pull system, the downstream process pulls items from upstream as they need it. A pull system is generally considered to be more efficient by eliminating overproduction upstream and excess inventory downstream. |
Search the Dictionary of Lean Six Sigma Tools/Concepts
