Methodology
How prices are collected
Prices come from uploaded quotations and invoices (processed automatically by AI into structured unit rates) and from manual submissions by signed-in contributors. Every submission is one observation, not an unquestioned market truth.
How the market figure is calculated
The Median is the primary reference figure — a simple average is avoided because a few extreme prices can distort it. The Market Range shows the typical central band (roughly the 10th–90th percentile) of usable observations from the last 6 months, expanding to 12 months when recent data is insufficient. Data older than 12 months remains visible as history but does not influence the current market figure.
Trust and confidence
Document-backed evidence (invoices, quotations) carries more weight than manual entries. Confidence reflects the amount of usable data, source diversity, recency and consistency — not submission count alone. Unusual prices are flagged for administrator review rather than assumed false; duplicate evidence counts only once.
Privacy
Original documents are never made public. Contributors choose whether the source company name is shown; if hidden, it is never exposed publicly while still being used internally for duplicate detection and trust evaluation.