Read across the table before reading the headline
In the October 2026 release, German industrial production for August was up 0.4 per cent from July but down 1.2 per cent from August a year earlier. The first comparison uses calendar- and seasonally adjusted data. The second is calendar-adjusted. A monthly recovery can therefore coexist with output below its year-earlier level. The figures describe output volume, not firms’ selling prices, revenues or profits. The euro area headline is not a substitute for the German country row.
Ask how much the calendar can explain
Imagine a factory producing 100 identical units every working day. Output of 2,100 units in a month with 21 working days becomes 2,200 in a month with 22. The unadjusted total rises nearly 4.8 per cent with no change in daily intensity. Official calendar adjustment uses statistical models, not this simple division; the example isolates the reason adjustment matters. Movable holidays, differing national calendars and regular factory closures complicate direct comparisons, particularly between neighbouring months.
Test whether the move is material for a business
Select a subsector that resembles the firm’s production, compare consecutive three-month averages and record the release date. A domestic production index does not capture the full activity of a business making some of its products overseas. New survey returns can also lead to revisions. Keep the first published observation if reconstructing what an analyst knew at the time, and use the latest consistent series for a retrospective account of the production cycle. A strong month in a small subsector deserves no extra weight merely because its data were the most recent to be published.
Practical check
Record geography, reference month, comparison period, adjustment and release date alongside each percentage.