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Single-source parts and inbound concentration by site: the supply chain continuity roll-up

How a supply chain team finds single-source parts, measures inbound concentration by supplier per site and watches supplier performance trends from goods receipts and the supplier master, with the reconciliation to goods received that makes the exposure figure defensible.

The short answerSingle-source exposure is every part with one qualified supplier, or one supplier actually used in the window, valued at annual spend or the cost of a month without it. Inbound concentration is each supplier's share of a site's receipts against a threshold. Both come from goods receipts joined to the supplier master, rolled up per site, and asserted against total goods received so the exposure figure can be put in front of the board.

Every supply chain knows its important suppliers. Few can put a number on what a month without one would cost, per site, or list the parts that depend on exactly one qualified source. The receipts and the supplier master have both. This guide sets out the continuity roll-up: single-source parts, inbound concentration by site, and the performance trends that warn before a supplier fails.

The measures

Per part:

Qualified sources = suppliers on the approved list for the part Used sources = suppliers with receipts in the window Single-source = qualified sources = 1, or used sources = 1

Per site:

Concentration = the largest supplier's share of the site's inbound value, against a threshold

Per supplier, month on month:

On-time = receipts on or before the promised date ÷ receipts Quality = receipts without rejection ÷ receipts

The rows you need

  • Goods receipts: one row per receipt with supplier, part, site, quantity, value, promised date and received date. From SAP, Oracle, NetSuite or an export from any of them.
  • Supplier master: identifiers and the qualified supplier list per part, or per category where parts are not managed individually.
  • Returns and rejections: optional, for the quality trend.
  • Dependency: optional, the cost of a month without each critical part.

Supplier identifiers only.

The roll-up

  1. Part by supplier by site: receipts, value, on-time, quality.
  2. Part: qualified and used sources, single-source flag, exposure value.
  3. Site: inbound share by supplier, concentration flag, single-source parts count and value.
  4. Company: assert that part receipts sum to the site, sites to the company, and the company to total goods received.

goods received = Σ sites = Σ suppliers = Σ parts

The by-supplier equality catches a supplier under two identifiers. The by-part equality catches a part renumbered in the master mid-year.

A worked example

One site, one quarter.

Supplier Inbound value Share Single-source parts On-time, this quarter On-time, prior
Supplier 1042 $4.1m 58% 14 91% 96%
Supplier 0377 $1.6m 22% 3 97% 97%
Supplier 2210 $0.8m 12% 0 88% 89%
Others $0.6m 8% 2

One supplier holds 58 percent of the site's inbound and is the only source for fourteen parts, and its on-time rate has slipped five points in a quarter. That row is the finding. The exposure, at annual spend, is $16m; at the cost of a month's stoppage on the fourteen parts, whatever the site's dependency table says, which is the number the board understands.

Where it goes wrong

Qualified list not maintained. A supplier qualified years ago and never used counts as a second source that does not exist in practice. Report qualified and used separately.

Parts at the wrong grain. Concentration measured on a category with fifty parts hides that one part inside it has one source. Measure single-source at the part.

Promised dates missing. Receipts without a promised date cannot produce an on-time figure. Count them and get the date onto the purchase order.

Intercompany suppliers. A sister plant appears as a supplier with high concentration. Flag intercompany and report it separately.

Every month, per site

Mapped once, the receipts export and the supplier master produce the exposure per site, the single-source list and the performance trends every month, reconciled to goods received. Covirage builds this from the export as it is. The supply chain page describes the setup, and you can upload a sample receipts export and see the roll-up on your own rows.

Questions people ask

How is single-source different from contract compliance?

Compliance asks whether spend went to the contracted supplier. Continuity asks what happens if that supplier stops. A fully compliant category can be entirely single-sourced, and consolidating spend to fix compliance makes concentration worse. They belong on the same page for that reason.

How is exposure valued?

Two ways, and both are useful: annual spend on the part, which says how much is routed through one supplier, and the cost of a month without the part, which says what a failure costs. The second needs a production or service dependency the supply chain team already knows.

What performance trends can receipts show?

On-time delivery from promised against received dates, and quality from returns and rejections where they are recorded. Month on month, per supplier, a slide in either is the early signal.