January's manufacturing figures did not move in one direction. In its March 6, 2017 release, the Census Bureau reported new orders up 1.2 percent to $470.2 billion and shipments up 0.2 percent to $478.3 billion. The durable-goods backlog, however, fell 0.4 percent to $1,114.1 billion. Reading these figures requires separating a month's activity from what remained at its end. [jan17prel]

New orders are a monthly flow, net of cancellations. Shipments are another monthly flow; unfilled orders are the backlog stock at month-end. The quoted backlog covers durable goods, whereas the headline order and shipment totals cover manufacturing more broadly. Subtracting those headline flows cannot reconcile that stock. New and unfilled orders exclude semiconductors; the dollar figures are seasonally adjusted, not inflation-adjusted. [jan17prel]

Release dates matter as much as observation dates. The February 3 report originally estimated December shipment growth at 2.2 percent, with shipments of $475.8 billion. The March release revised December growth to 2.5 percent before reporting January's 0.2 percent increase. Mixing the original December level with January's later estimate would mix vintages. Both publications belong to the same Census evidence chain. [jan17prel][dec16prel]

There is also a limit to the precision readers can assign. This survey is not based on a probability sample, so Census cannot compute sampling errors or confidence intervals for these estimates. That does not make the estimates error-free. The usable reading is a set of dated, differently scoped measurements, not a statistically certified finding that all factory demand strengthened or weakened. [jan17prel]

Source documents

  1. Manufacturers Shipments, Inventories and Orders, January 2017https://www.census.gov/manufacturing/m3/historical_data/pressreleases/prel/2017/jan17prel.pdf
  2. Manufacturers Shipments, Inventories and Orders, December 2016https://www.census.gov/manufacturing/m3/historical_data/pressreleases/prel/2016/dec16prel.pdf