The three data formats QR loves — and the fast route through each.
Spend the first seconds on the furniture, not the numbers: units, axis scales, row and column totals, footnotes. Most QR errors are misreads — thousands taken as millions, per-month taken as per-year — not miscalculations. A five-second scan of the table beats a perfect calculation of the wrong cell.
Whatever the question — speed, cost per kilogram, parts of a ratio — reduce to the value of one part or one unit of time first, then scale up. Write the units down as you go; they tell you whether to multiply or divide, and unit traps are QR's favourite distractor.
On bar and line charts, read the two values the question actually needs and ignore the rest of the picture. Long multi-step table questions are the ones to flag early: a ninety-second question is two others you never reached. Estimate, eliminate the options that are miles off, and commit.