Operations and Process Management
Describe the process first
Process mapping (flowcharting) and value stream mapping expose steps, handoffs, decision points, and queues. Lean thinking targets the eight wastes (often memorized as TIMWOOD: transportation, inventory, motion, waiting, overproduction, overprocessing, defects, underused talent), supported by 5S, standard work, and error-proofing (poka-yoke). Six Sigma's DMAIC (define, measure, analyze, improve, control) suits data-rich defect problems; PDCA/PDSA suits rapid iterative improvement.
Flow metrics
Cycle time is the time one unit takes from start to finish; throughput is units completed per unit time; work-in-process (WIP) is the units in the system. Little's Law ties them together: WIP = throughput × cycle time. Capacity is the maximum sustainable output, and the bottleneck (constraint) sets the pace for the whole process. A classic trap: speeding up a non-bottleneck step yields almost no gain in total throughput - only relieving the constraint does.
Turnaround time and staffing
For TAT, report the median and a high percentile (such as the 90th) rather than only the mean, because TAT distributions are skewed by outliers. Workload-based staffing converts test volumes and productivity standards into required worked hours, then divides by productive hours per FTE (paid hours minus orientation, breaks, meetings, and paid leave) - dividing by 2,080 paid hours overstates capacity.
Worked example
An accessioning area holds 60 specimens in process and completes 30 per hour. By Little's Law, cycle time = 60 ÷ 30 = 2 hours. Cutting that queue to 30 specimens halves cycle time to 1 hour without any change in test speed.