Term | Definition |
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Value Stream Map (VSM) | Similar to a process map, it diagrams the flow of a process. However, it doesn't document decision points or detailed process steps, but instead focuses on the timeliness (efficiency) within the flow of products through the process by tracking value-added and non-value-added steps, process cycle times, take time, inventory, staffing, etc. |
Value-Added (NVA) | A step in a process that adds value (as defined by the customer's requirements) and represents what the customer is willing to pay for. |
Variance | The average squared deviation (or differences) about the mean or (X - μ)2 / N or σ2. It's intended to measure how spread out the distribution is from the mean. |
Variation | See Spread |
Voice of the Customer (VOC) | A term describing what the customer wants or is willing to pay for. It statistically represents the lower/upper specification limits (LSL/USL) of a distribution where any data point or observation falling within those limits is considered to be acceptable by the customer and anything falling outside those limits is unacceptable or a defect. This is contrasted with the Voice of the Process (VOP). |
Voice of the Process (VOP) | A term describing the measurable capability or performance of a process. It statistically represents the full range of observations (or capability) of the process and is compared to the Voice of the Customer (VOC). If the VOP extends beyond the VOC, then the process is failing and should be analyzed to find how to reduce the variation and improve the process capability to meet the customer's needs. |