Definition
A set of tools to identify and remove causes of process variability.
In detail
Variation Reduction Kaizen (VRK) is a toolset for identifying and eliminating root causes of process variation, the Six Sigma system's application within the Danaher Business System. Its main line is a seven-step sequence that must be followed in order: record the current process → draw a cause-and-effect diagram → mark each cause C or N (X is not used at this stage) → use an SOP to turn an N into a C → implement → draw the CAN-BE future state → record results. Unlike Standard Work (SW), which focuses on "executing to standard," VRK asks "is the standard itself stable"; a control chart is used only to verify after improvement, not as a starting point, and complements the monitoring function of Statistical Process Control (SPC). Typical outputs include a kaizen week report, a CNX variation-source table, a record of SOP-level upgrades, and updated standard work.
Example in practice
An injection molding shop had large dimensional variation, increasing customer complaints. During a kaizen week the team followed the seven VRK steps in order: recorded the current process, drew a cause-and-effect diagram listing possible causes, marked each one C (does not change over time) or N (changes over time), identified uneven mold temperature as the main N-type cause, used an SOP to turn it from N to C (Level 3: installed a constant-temperature control device, an irreversible change), then drew the CAN-BE future state and recorded the results. The control chart was used afterward only to verify that the variation was now controlled; the team wrote the new parameters into standard work and reviewed them periodically.