Theory of Constraints Handbook - James Cox Iii [74]
Step 5: Implement Surrounding Processes
After reducing WIP and establishing task management, the benefits of synchronization will already be evident. Projects will be completing faster, firefighting and multitasking will be substantially less, and managers will feel more in control. However, the following surrounding processes are also needed to complete the picture.
Project Control
This is typically a formal weekly process to respond to uncertainties such as scope changes, technical problems, etc., that cannot be combated through routine task management. If the rate of buffer consumption (percentage buffer consumed versus percentage work completed in the longest leg) is too high, then project managers know which legs of the project are in the “red.” They can then develop and execute recovery plans for those legs. Recovery plans can consist of run-of-the-mill items like scope adjustments and overtime as well as unique, even brilliant, solutions for specific situations.
Pipeline Control
While project managers can keep the buffers within their individual projects in control, it works only when just some projects are “red.” If most projects are running behind schedule, there is probably a more systemic or global issue at play that is affecting all projects in the pipeline. This is where senior managers step in and make global decisions like putting some projects temporarily on hold, reprioritizing projects, or authorizing across-the-board overtime.
For example, about a year after the initial implementation at an aircraft maintenance and repair depot, the number of red projects jumped from 30 to 70 percent. The underlying reason was a sudden increase in the sheet-metal work required on incoming aircraft. During the three months it took to ramp up sheet-metal capacity, the number of active aircraft in the sheet-metal department was reduced from four to three and the maximum allowed overtime was authorized. As a result, the duration of the sheet-metal phase came down from 65 days to 47 days; projects trended back to “green” and the required Throughput rate was achieved.
Pipeline Planning
During WIP reduction (Step 2), Execution is monitored to verify that the initially selected drum is still valid. If the original drum is getting starved for projects, then the real drum could be an earlier phase or an upstream resource; similarly, if queues build up downstream of the original drum, then the real drum could be a later phase or a downstream resource. The drum can be changed if such conditions persist.
In the event the drum changes, managers formally meet to reset project priorities and possibly revise due-date commitments. Then decisions about project priorities can be made routinely as new projects are undertaken or as business conditions change.
While actual decisions are made by managers in charge of the project operations (in consultation with other affected functions such as manufacturing, sales, and marketing), a dedicated “Master Scheduler” or “Pipeline Analyst” is typically required to provide analytical support.
Capacity Management
The loop is closed with a capacity management process that identifies and mitigates resource shortages. The required information comes from an aggregate database of project plans, which shows the total resource “load to capacity,” as well as buffer analysis, which identifies the resources that drive high-buffer consumption.
An important point is that the capacity of resources that are recovering buffers should be maintained or even increased (at least temporarily), even if it shows up as excess capacity in the “load to capacity” view.
In IT and engineering projects, for example, subject matter specialists do not have many explicit tasks in the project plans. A “load-to-capacity” view will show them as being 20 to 30 percent utilized. However, these specialists are vital for recovering buffers. Keeping their planned workload at 20 to 30 percent is a good practice that ensures both project delivery and pipeline Throughput.
Step 6: Identify Opportunities