Methodology
Government procurement data sources and methodology
Methodology
This page lists the government procurement data sources behind every figure on NSN Explorer and explains how each one is used. Prices, solicitations and contract totals come from three public systems: DLA's DIBBS bid board, SAM.gov contract notices and USAspending contract actions. The index is rebuilt every day, nothing is estimated or modeled, and every number links to the record it came from so a supplier, buyer or reporter can check it. The site is free.
Unit prices — pub.price_points
Every dot on a price chart and every row in a purchase table is one government purchase at one unit price, sourced from either a DIBBS award record or a USAspending award record. Each price point stores the underlying source URL, and the build refuses to publish a price point without one — that check runs in the data-load step of the site build, not just as a database constraint.
Contract action totals — pub.contract_actions
USAspending publishes agency-wide contract actions with obligation totals — the amount obligated on a contract action, not a per-unit price. We show these on NSN pages, clearly labeled as "contract action totals, not unit prices," and they never appear on a price chart, which is unit-price data only.
AMSC / AMC — pub.amsc_observations
The Acquisition Method Suffix Code tells you whether a part is open to competition (AMSC G) or sole-source because the government says it lacks the technical data package (AMSC C, D, H, Z). We show the most recently observed value with the date and source solicitation it was observed on.
DIBBS data explained
DIBBS is the DLA Internet Bid Board System, where the Defense Logistics Agency posts requests for quote and records awards. NSN Explorer reads each open solicitation's NSN, item name, quantity, return-by date and set-aside or competition code, and each award's unit price, quantity and winning supplier. Solicitations are kept after they close so the demand record grows over time. Every DIBBS row on the site links to its record at dibbs.bsm.dla.mil.
Price spikes and "overcharges"
A purchase is flagged as a spike when its unit price is at least 3× the NSN's trailing median price at that point in time. On category pages, a row is highlighted when the most recent purchase is at least 3× the NSN's historical median. This is a mechanical threshold, not an accusation — it's a starting point for a supplier sanity-checking a quote, or for a buyer's, researcher's, or reporter's own follow-up questions, and every flagged purchase links to its source record.
Coverage
We currently fully index 426 Federal Supply Classes ("deep" categories) covering 35,577 NSNs, 0 priced purchases, and 95,059 contract actions totaling $309,445,614 in indexed spend. Government-wide long-tail coverage (millions of NSNs) is on the roadmap; see /browse/ for the current list.
Methodology questions
What government procurement data sources does NSN Explorer use?
Three: DLA DIBBS for solicitations and awards, SAM.gov for contract notices and USAspending for contract actions. All three are public and free.
Is any figure estimated?
No. Every price, quantity and total is copied from a government record and links to it. The site build rejects any price point without a source URL.
How often is the data refreshed?
The site is rebuilt every day from the source systems, and open solicitations are re-crawled more often. Records may still lag the underlying events.
What does a price spike mean?
A purchase is flagged when its unit price is at least three times the NSN's trailing median. It is a mechanical threshold to prompt a closer look, not a finding.