TLDR. Weighing what leaves your warehouse proves tonnage, not diversion. Diversion requires knowing what would have happened to the item if you had not taken it, and the only people who know that are your donors. Put one question in a post-pickup survey. One bank asked 415 donors and found landfill was the majority answer — which is what turns a tonnage figure into a defensible environmental claim.
The hole in most diversion claims
Nearly every furniture bank reports tonnes diverted from landfill. Almost none can evidence the second half of that sentence.
You can prove the tonnage. You weighed it, or you have the scale tickets. What you usually cannot prove is the counterfactual: that the sofa was headed for the kerb rather than to a cousin, a buy-nothing group, a consignment store, or a different charity. If it would have been reused anyway, you moved it — you did not divert it.
This matters because the sophisticated funders now ask. A municipal waste department, a corporate ESG team and any assurance process worth the name will all want to know how you established additionality. “We weighed it” is not an answer to that question.
The question that closes the hole
Ask the donor what they would have done otherwise.
It costs one question in a survey you are probably already sending. Furniture Bank in Toronto ran this across 415 donor respondents in its 2023 social value study. The largest single response was that the items would have gone to landfill. The rest split across selling them, giving them to another charity or thrift store, and passing them to friends or family.
That distribution is the finding. It tells you what proportion of your tonnage is genuinely additional, and it lets you discount the rest rather than claiming all of it and hoping nobody checks. A bank that reports “919 tonnes diverted, of which we attribute X% as additional based on donor-reported alternatives” is in a completely different credibility position from one reporting a raw number.
Two other findings from the same survey are worth collecting while you are in there: 92.5% of donors agreed that donating made them feel more connected to their community, and 79.7% that they felt they were giving back to the planet. Those are donor outcomes, and donors are a stakeholder group most banks forget to measure at all.
How to field it without annoying anyone
- Send it after the pickup, not before. The donor has had the experience and has nothing left to arrange.
- Keep it to five questions or fewer. The counterfactual question, two outcome questions, and a free text box will carry most of the weight.
- Offer the alternatives as options, not as free text. “Landfill or bulk waste pickup / sold it / another charity / friends or family / kept it” codes itself. Free text does not.
- Ask every donor, not a sample. Response rates will do the sampling for you, and a census avoids having to defend a sampling frame.
- Do not change the wording between years. The moment you do, your trend line is gone.
Aligning to a standard so the number travels
A diversion figure that only exists inside your own methodology is worth less than one that maps to something a funder already recognises. Two are worth knowing:
- Social Value International — the standard the SROI methodology sits under, and the one that requires you to consider deadweight and attribution rather than claiming gross outcomes.
- Canada’s Common Approach to Impact Measurement — a shared framework designed so that results from different organisations can sit beside each other.
Toronto’s 2023 study adhered to both. That is the reason its $39.5 million of social, environmental and economic value and its $5.76 per dollar invested were quotable rather than merely calculated.
What the number looks like once it holds
Toronto’s 2023 environmental figures: 47,419 pieces of furniture diverted, 919 tonnes by weight, and 2,214 tonnes of carbon abated as a result. The following year the tonnage rose to 953 and the social return moved from $5.76 to $6.49 per dollar.
Note what makes that pair of years useful — not the size of either number, but the fact that the definitions did not move between them. A trend you can defend beats a headline you cannot.
Where to go next
- What should a small furniture bank measure first? — the six counts that come before any of this
- What does it take to build a full impact measurement system? — the three-year version
- Can I compare my SROI to another furniture bank’s? — why the ratio is not the comparable part
