We issue monthly diversion statements to customers who want them: tonnage reused, tonnage recycled, landfill avoided, estimated CO₂e avoided, and contamination rate. The last one is the one that occasionally embarrasses us, and it is the reason the rest is worth anything.
What happened in 2023
We took on a large customer whose waste stream we had assessed from a site visit and a description. Both were accurate as far as they went. What neither captured was a seasonal line that ran four months a year and produced a significant volume of film-wrapped material that nobody had mentioned, because to them it was not packaging — it was product protection.
Our contamination rate on baled OCC rose from 1.9% to 3.4% over two quarters. Two bales were downgraded at the mill. We reported the figure in the normal monthly statement, with an explanation.
What it cost
A prospect in the middle of a procurement process saw the rising number in our reference material and chose a supplier whose reported figure was flat at 0.8%. We do not know whether that figure was accurate. We do know that a flat contamination rate across eight quarters is unusual enough to be worth a question.
Why we did not just smooth it
Because the alternative is a number that means nothing.
A figure you only publish when it flatters you is marketing. It is not measurement, and your sustainability team cannot audit it.
If we report contamination only when it is good, a customer reading our statement learns nothing about our process — only about our editorial policy. The whole value of the number is that it moves.
What we actually did about it
- Added a separation step on inbound from that customer, before material reaches the baler.
- Changed our site assessment questionnaire to ask about product protection materials, not just packaging. The gap was in our question, not in their answer.
- Started reporting contamination by source where a customer's volume justifies it, so problems are attributable rather than averaged.
- Published the revised figure each month until it came back down, which took a further two quarters.
The broader point about reported numbers
Packaging and waste services are full of figures that are technically true and practically meaningless. 100% diversion computed on a denominator that excludes residuals. Carbon savings that include end-of-life recycling credit, stored fibre carbon and avoided landfill methane, all of which are contested and all of which flatter the number.
We exclude all three from our own carbon figures, publish the coefficients we do use, and send the underlying spreadsheet to anybody who asks. Two of our published coefficients have changed because a customer arrived with better data. That is the point of showing the workings.
What to ask any supplier
- Show me a period where this number got worse, and what you did.
- What is in your residual fraction, by material?
- What coefficients are behind your carbon claim, and what did you exclude?
- Who audits this, and will you send me the raw data?
A supplier who can answer all four is measuring. One who cannot is reporting.
Our pieces are written by the people who do the work rather than by a content agency, which is why they contain more numbers and fewer adjectives than is fashionable. If a figure here does not match your experience, we would genuinely like to hear about it — two of our published coefficients have changed that way.