Compare like with like

Four coordinates before any comparison

An analyst's spreadsheet has two cells: Larkstone Foods revenue 500, Vellmar Foods revenue 620. The boss asks which company is bigger. Larkstone reports in US dollars, in millions, for a 53-week fiscal year. Vellmar reports in euros, in thousands, and the 620 is a half-year figure. The question cannot be answered until the coordinates match.

Every number needs four coordinates: which business, which period, which units, which definition. Which business includes the perimeter: consolidated Larkstone is not its bakery segment. Which period: year-to-date cash flow is not quarterly cash flow. Which units: millions of euros are not thousands of dollars. Which definition: "revenue" in one filing may be net of items another filing leaves in. This is the stage's question, what is the evidence, applied to the number's own label.

Build the last twelve months

Larkstone's prior full-year revenue is $500m. Its prior first half was $220m; its current first half is $270m. Last twelve months = 500 − 220 + 270 = $550m. You keep the prior second half, drop the stale first half and add the fresh one. Adding 270 to the full year gives 770, an eighteen-month total, and doubling the new half assumes a business with no seasons.

Periods that look alike and are not

Quarterly Cash Ledgers (cash flow statements) usually show year-to-date amounts. Larkstone's operating cash flow reads $40m in its Q1 10-Q and $90m in its Q2 10-Q, so the standalone second quarter is 90 − 40 = $50m, not $90m. Check for restatements and classification changes before subtracting, or the two YTD figures will not be on the same basis.

Fiscal calendars differ from the calendar year and from each other. Larkstone's 53-week year carries roughly 2% more selling days than a 52-week one, which shows up as growth before a single extra customer arrives. Acquisitions and discontinued operations change the perimeter, so a reported year may hold only part of a year of a bought business. Currency translation and constant-currency metrics add one more bridge that needs a stated method.