One of the challenges in implementing Continuous Improvement is developing an effective value stream map for the process being examined. There are many ways to draw a value stream map, but some provide higher quality information than others. Most value stream maps have these components:
- Use blocks to identify the major process steps.
- Identify the flow of work with arrows, showing a supplier at the beginning and a customer at the end of the map.
- Identify process times and delay times between processes.
Within the past four years (from 2010) the work of Karen Martin and Mike Osterling (1) has added a new dimension to value stream maps by identifying the percent complete and accurate for each process step in the value stream. This overall percent defines the percent that inputs to the process box are both complete and accurate from the previous process box.
Exhibit 1 shows a value stream map for patient flow in a healthcare clinic with the typical supplier, process boxes and customer designations along with process times (P/T) and delay times (D/T). On this process map a new row at the bottom shows "percent complete and accurate (%CA)" for the work coming into the process box from the previous process box.
The %CA indicates that all of inputs to the process box are both complete and accurate. That is, if 90% of inputs (information supplied) are complete and accurate to the customer in following the process block, the %CA designation is 90%. That is, ten percent of the time, the information from the previous step in the process must be corrected, has missing information located or clarification must be obtained. And, as shown in Exhibit 1, the overall %CA for the process is found by multiplying the %CA block together of all of the process blocs [Value Stream Summary: %CA = 69%]
The %CA measure measures both delays and defects in the value stream and gives measure of overall performance of the value stream. One of the next steps in improvement is defining each of the defects and delays and moving the %CA toward 100 percent.
We recommend that when process improvement measures are being defined for a value stream that percent complete and accurate (%CA) measures be included.
Notes:
1. The Kaizen Event Planner - Achieving Rapid Improvement in Office, Service and Technical Environments, by Karen Martin and Mike Osterling, CRC Press, 2010, CRC Press Group