Families of variation

positional, cyclical and temporal variation

Positional (within-piece) variation: taper, ovality, differences between cavities or positions on the part. Cyclical (piece-to-piece) variation: differences between consecutive parts. Temporal (time-to-time) variation: drift and shifts over hours, shifts or batches.

Each family has typical causes, so knowing the largest one narrows the search.

Calculate it

Multi-Vari Chart and Box Plot: Multi-vari chart, families of variation and box plots for root cause work.

Related terms

• Multi-vari study: which family of variation is the largest