Written by L. Park, Sustainability
When we decided to publish our first audited sustainability report in 2022, we thought the audit itself would be a formality. We had been keeping good records for years. Our scale tickets were tidy. Our WMS logs were complete. The auditor arrived, spent two days at our yard, and then handed us a list of fourteen findings — none of them catastrophic, but all of them embarrassing in retrospect. Here is what we learned.
Lesson 1: methodology has to be written down.
We had been calculating CO2 avoidance using the EPA WARM model for years, but we had never actually written down which version of the model, which assumptions, and how we were converting our internal units to model units. The auditor flagged this on day one. We now keep a one-page methodology document attached to every report and update it whenever the EPA updates the model.
Lesson 2: source data has to survive a year.
Some of our scale tickets from 2018 had been thrown away because they were the kind of paper that fades after a few years. We could prove the totals from the WMS, but we could not produce the original documents. The auditor was forgiving but made the point that, in a stricter audit, that gap would have been a finding. Now we scan every paper ticket and store the scans for seven years.
Lesson 3: round numbers are suspicious.
Our 2021 diversion total had ended in three zeros. The auditor specifically asked why. The answer was that we had rounded to the nearest hundred tons for "readability" in the previous public report. He gently explained that round numbers in audited reports are a red flag and that we should publish exact figures with confidence intervals, not pretty round ones.
Lesson 4: include your gaps.
We had not mentioned that 4% of our outbound trucks deadhead. The auditor pointed out that omitting unfavorable data is one of the top reasons sustainability reports lose credibility, even when the omitted data is small. We added the 4% deadhead number to the next report, explained why, and described what we were doing about it. Customers actually liked the report better with the gap acknowledged.
Lesson 5: every claim needs a footnote.
If you cannot point to a data source for a claim, do not make the claim. This rule sounds obvious, but the first draft of our 2021 report had several sentences that started with "we believe" or "we estimate" — which is fine for casual writing but indefensible in an audit. We now require every claim to have a footnote that points to a specific document, log, or third-party source.
The best part of the audit.
After the auditor handed us his list of findings, he also told us that the underlying data was solid and that fixing the methodology gaps would result in a strongly defensible report. Two months later we published our first audited sustainability report. We sent it to every customer in our database. Three of them asked us to help them set up similar reporting. That is how compliance work pays for itself.