Nature of work analysis concerns the evaluationof deciding whether any sub-process or process step is value adding or non-value adding. This level of analysis is taking your intitial value add process evaluation down to the next level of detail. Just as you looked at the overall process for waste and redundancy, you will apply this same thinking but to each sub-process or even individual process step. Each step that has been determined to be non-value added by a nature of work analysis, may then be further categorized into:
- In-house failures: These are procedures or procedure steps involving rework to correct errors or defects in the process. They will almost always be identified by the prefix "re", as in re-work, re-test, re-peat.
- Peripheral failures: These are errors or defects which like involve rework, but are those which are not discovered within the process, but are discovered and identified by the customer. These are true process failures.
- Control or inspection failures: These are procedures aimed at correcting errors, and involve rechecking, verification and corrections. Though they may be necessary in some instances, they are considered non value added steps.
- Delays or wait times: These are the most commonly seen non value adding steps. This will be evident when there is a build up at process points of inventory, work in progress (WIP), or bottlenecks.
- Lead times: The procedures which involve set up and "getting ready" to begin processes. These can be non value added when they are excessively or unnecessarily long and this extra time causes the process end time to fail to meet customer expectations.
- Movement failures: This failure involves unnecessary movement times to gather raw materials or movement of finished product to the customer. It is usually considered non value added activity.