The Spec Desk · Methodology
How the Spec Desk computes its figures
The Spec Desk is SpecIndex's data publication. Its stories lead with numbers from the index, and this page states how those numbers are produced, so that anyone quoting a figure can say what it counts, what it covers, and when it was measured.
The source class
Every figure the Spec Desk publishes is counted from the SpecIndex index of public bid documents: the project manuals, addenda and bid sets that public owners publish for bidding. That is the whole source class. Privately bid work produces no public specification and does not appear in the index, so no figure here describes it, and the Desk does not estimate it.
Positions, cited to the page
The unit the Desk counts is the specification position: a place where a specification names a product or a manufacturer, classified as basis of design or approved equal under the index's documented definitions. Every position in the index is cited to the document it came from and the page it appears on. A figure in a story traces to those cited positions, and the story's sources name the records behind it.
We label a position proprietary only when the specification text expressly bars equals or substitutions. The index is not publishing that label today: it is withdrawn while it is re-derived to that standard, so no figure on this desk counts proprietary positions.
Counted in full, not sampled by default
Where a figure describes the index, it is counted over every record that meets the stated scope, in the same pass that produces the rows behind it, so the count and the records can never disagree. Where a figure rests on a narrower stated population, such as a panel of brands or a set of states, the story says so in its method note, and the figure describes that population rather than the whole index.
Population, window and method, stated with the figure
Every statistic the Desk publishes carries three things with it: the population it was counted over, the window it covers, and how it was counted. They appear on the page or in the story's own method note. A figure that cannot state all three does not publish.
The window
The index reads public bid documents from January 2025 onward. Documents published before that window are not in the index, and no figure describes them. When the window moves, this page moves with it.
As of dating
A measured figure carries the date it was measured. A live figure is read from the index when the page loads and carries the index's own computed time with it. When a story's figure is corrected, the story's updated date changes, and the figure's as of date changes with it, so a reader can always tell which version of a number they are quoting.
Read the stories on the Spec Desk, or look a figure up in the index itself with a free brand check.