A percentage is incomplete without its denominator. A team can contribute forty percent of one region and twenty percent of the whole organisation at the same time. The report becomes misleading when the heading fails to say which comparison it shows.

Start with a practice PivotTable in desktop Excel for Windows. Use Region above Team in the Rows area and sum a numeric Units field. Give East teams A and B 20 and 30 units, and West team C 50 units. East totals 50; the overall total is 100.

Keep the underlying value visible

Excel lets you add the same value field to the Values area more than once. Drag Units into that area again, placing the copy below the existing field. Keep the first field as the raw summed value. On the second, right-click a value and choose Show Values As, % of Parent Row Total.

That option divides an item's value by its parent item on the rows. For comparison, add a third copy and set Show Values As to % of Grand Total, which uses the report's overall total. Give the value columns clear captions describing their calculation.

Read team A across the row. The expected values are 20 units, 40% of East and 20% of the overall total. Check 20 divided by 50 and 20 divided by 100 independently. A percent sign changes the display's unit; the selected calculation establishes the denominator.

Test the hierarchy, not just one cell

For team B, expect 30 units, 60% of East and 30% overall. The two team percentages within East should account for their parent in this complete example. Team C supplies all of West's 50 units, so it contributes 100% of its parent while remaining 50% of the organisation.

Inspect the actual row nesting before applying this to another report. If Team and Region are reversed, the word parent no longer describes the intended Region-above-Team structure. Do not carry a correct-looking caption into a different hierarchy without rechecking what it divides by.

Record the report's current selection and inclusion rule with the output. After changing a filter or the set of records, recompute one numerator and its intended denominator from the selected data instead of assuming the earlier percentage remains comparable.

Keep the raw value alongside the ratio when it helps readers assess scale. An accepted report lets another person explain both forty percent and twenty percent from the same twenty units, without guessing which population the heading represents.

Sources: Microsoft: PivotTable percentages.