In Taiwan group audits we still meet teams who open planning with a single revenue percentage and call the job done. That shortcut fails when gross margin is thin, when one component holds most inventory, or when related-party sales inflate top-line figures that do not drive risk.
We begin with the reporting pattern the board actually watches: contribution margin, inventory days, or operating profit. From there we set overall materiality, performance materiality, and clearly trivial thresholds, then document why those anchors fit this entity — not last year’s peer average.
What goes in the planning memo
The memo states the chosen benchmarks, the percentages applied, and the qualitative factors that could still matter below quantitative thresholds (related-party disclosures, covenant clauses, first-year consolidation). Fieldwork teams receive those numbers before sample sizes are locked.
When figures change mid-season
If management revises a material estimate after interim work, we revisit performance materiality rather than silently stretching sample coverage. That conversation is uncomfortable; it is also cheaper than rebuilding binders in March.