Workflow Analysis, Process Modeling, and Business Process Improvement
Workflow analysis and process improvement test whether you can model a process, measure it, find the constraint, and prove that a change improves flow. Expect BPMN notation, value stream mapping, Little’s Law, bottleneck analysis, root-cause tools, and DMAIC.
Core rules
- Model the as-is process before proposing the to-be process. Define start and end events, activities, gateways, and swimlanes for accountable roles.
- Measure cycle time, throughput, work-in-process, and utilization. Little’s Law: WIP = throughput × flow time, with consistent time units.
- The bottleneck sets system throughput. Improving a non-bottleneck usually adds WIP, not output.
- Distinguish value-added time from waiting, transport, inspection, and rework. Most elapsed time is usually waiting.
- Use DMAIC for structured improvement: define, measure, analyze, improve, control. Verify with data after the change.
Worked example
A claims desk has 240 open claims and completes 40 claims per day. Little’s Law gives flow time = WIP / throughput = 240 / 40 = 6 days. The target is 3 days at the same throughput, so required WIP is 40 × 3 = 120 claims. The reasoning shows that capping intake or reducing WIP, not exhorting staff to work faster, is the lever. If the desk instead raises throughput to 80 per day, 240 claims would clear in 3 days only if WIP is held constant; otherwise queue time grows.
Traps
- Confusing capacity with cycle time: capacity is output per period; cycle time is time per unit or between completions.
- Drawing a BPMN diagram with activities but no end event or with gateways that neither split nor merge.
- Measuring touch time and calling it lead time.
- Improving a non-bottleneck and claiming throughput gains.