The lead and the invoice live in the same database. The link between them often does not.

An integrated system makes it possible to follow a lead through to an invoice, and that possibility is only realised when every step was completed in order.

In practice a salesperson creates a new customer rather than converting the lead, a quotation is raised against a different contact, or the invoice goes to a company when the lead was a person.

Each break leaves the invoice without a source, and a report that follows internal links attributes it to nothing.

Joining on the contact detail reconnects them, and the report shows which matches came through the internal chain and which had to be rebuilt.

The share that had to be rebuilt is itself worth knowing. It measures how the sales process is actually used, as against how it was designed.

Many companies start with one part of an integrated system — often the CRM or the invoicing — and run the rest elsewhere for years.

A company using its CRM without its accounting has leads and no invoices in the same place; one using its accounting without the CRM has invoices and no sources.

The method works either way, because it needs two exports rather than one integrated setup: leads from wherever they are kept, invoices from wherever they are raised.

That also makes it robust to the next change of system, which in growing companies tends to come sooner than planned.

The step from quotation to invoice is where scope changes, discounts get applied and some confirmed orders are never invoiced at all.

Ranking sources on confirmed quotations measures the sales team's optimism; ranking on posted invoices measures the money.

Where both are exported, the gap between them per source is worth a look once. Sources that produce price-sensitive buyers usually show the widest one.

The report ranks on posted invoices and labels the basis, so the number can be defended when somebody asks.

Where customers are billed monthly or annually on a subscription, one sale produces a long series of invoices.

Credited invoice by invoice, the source that produced the customer gets paid again every month and looks far better than a source whose customers buy once.

Summing by customer across the window and keeping the first invoice apart from later ones gives both the acquisition figure and the retention figure without mixing them.

That split also shows which sources produce customers who stay, which is usually the more valuable finding. A source whose customers cancel after two months was a source of trials, however good its first-month figure looked.