DSO does not measure how good you are at collecting

DSO is the figure that gets reported. It is also the one most often misread — not because it is wrong, but because it measures two things at once and does not say which of them moved.

Give a large customer 60 days instead of 30 and your DSO rises. Not because anyone got worse at chasing, but because you sold on different terms. If revenue falls in a quarter, DSO falls too, without anything good having happened.

The figure that measures only the work

CEI asks a narrower question. Not how long it took, but how much of what was actually collectable in the period you in fact collected. Payment terms do not enter into it, because anything not yet due is held outside.

::figur[cei]

Both companies in the figure have a DSO of 52 days. One sells on 45 days of credit and brings in almost everything on time. The other sells on 20 days and lets a quarter of the portfolio slip. On DSO alone they look alike. On CEI they do not.

Why the difference matters in practice

If DSO is the only figure on the report, the easiest route to an improvement becomes tightening the payment terms. That works on paper and costs sales in reality.

The other route — bringing in more of the money already overdue — moves CEI without touching a single customer agreement. It is the route that is free, and it only becomes visible if somebody measures it.

What belongs on the report

Both figures, side by side, with an ageing breakdown beneath them. DSO tells you how long your cycle is. CEI tells you whether you are holding it. The ageing tells you where the problem sits.

One figure on its own invites the wrong decision. Not because DSO is a poor metric — but because it answers a different question from the one most people think they are asking.