Calculated Fields Create New Data, Not New Truth
Use calculated fields deliberately by naming the business rule and aggregation level.
A formula is not complete until the aggregation story is explicit. The mechanism A calculated field is a new field whose values are determined by a formula you control. That sounds simple, but the real skill is naming the business rule and its level. Row-level calculations run before aggregation; aggregate calculations operate after values are summarized in the view. Ratios are the classic trap: AVG([Profit]/[Sales]) answers “average order-level margin,” while SUM([Profit])/SUM([Sales]) answers “overall margin.” Both can be valid, but they are not interchangeable. The mechanism is aggregation. Tableau must decide whether to calculate first and then aggregate, or aggregate first…
Sign up free — one personalized lesson every day, matched to your role and goals.
Already have an account? Sign in