Methodology

How we source, verify and present market data, supplier records and editorial content across the Commodities.tz network.

Market data

Every price series distinguishes its price type — farm-gate, auction, wholesale, export, international/reference, or indicative — along with market, location, grade/specification, currency and unit. We do not present prices of different types, grades, locations or marketing seasons as directly comparable. Each observation carries an observation date, a cited source, and the date we retrieved it. We never interpolate or invent data points to fill a chart: where the historical record is incomplete, the chart is incomplete, and we say so.

Supplier verification levels

• Listed — publicly discovered (e.g. via a business registry, trade directory or the supplier's own public materials) but not independently confirmed by us.
• Source-confirmed — corroborated by a credible public industry or government source (a commodity board register, an export directory, official statistics), which we cite on the supplier's profile.
• Verified — an administrator has completed our verification checklist for this specific business: confirming its business identity, the claimant's relationship to it (where a profile claim was involved), a public business presence, activity consistent with the commodity it lists, and a working contact point. We record the date, the reviewing admin, and a basis note for every verified supplier. Verification is not automatic — a supplier cannot request or pay for it, and completing our supplier-claim process does not by itself grant it.

What "Verified" does not mean: it is not a government certification, a guarantee of financial solvency, product quality, delivery performance, or ongoing legal compliance, and it is not permanent — we set a review date for every verified supplier and re-check it periodically. A supplier is never publicly flagged as "expired" or "invalid" merely because a scheduled review is due.

Suppliers can ask to have their existing directory listing claimed via a "Claim this profile" link on their profile page. A claim confirms who represents a listing so we know who we're talking to — it is reviewed separately from, and does not by itself change, verification status.

Sourcing priorities

We prioritise Tanzanian primary sources — commodity boards, ministries, the National Bureau of Statistics, the Zanzibar Office of the Chief Government Statistician, and the Tanzania Trade Development Authority — supplemented by international references such as FAOSTAT, UN Comtrade, the International Trade Centre, and the relevant international commodity organisations. We do not build claims primarily from generic blogs or unsourced aggregator sites.

Corrections

If you believe something on this network is inaccurate or out of date, please use our Corrections page — we review every report.