You know the sequence.
The survey goes out. A third of them answer, mostly the ones already doing something. The portal gets built and the login emails go unopened at a rate nobody wants to put in a slide. You send the second reminder, then the third with your director copied, which everyone understands is what a third reminder means.
The responses that come back are estimates dressed as data. Somebody's intern filled in a spend-based figure and nothing about the actual product changed.
Then the deadline arrives, you fill the gaps with secondary factors, and the number gets reported. It describes an industry average applied to your spend. Nobody did anything differently to produce it.
Year after year, supplier engagement gets named the biggest obstacle in Scope 3. The tooling improves every cycle. The behavior does not.
Why the data framing keeps failing
Most of what gets called engagement was never designed to change how work happens.
Data demands go out by email with little context and no support. Suppliers are asked to commit to science-based targets while headquarters is still working out its own plan. Competition between them gets treated as a motivator, with nothing said about transition risk or the equipment they would be stranding. Transparency is assumed to create capability, as though a supplier who can see the problem can therefore solve it. And compliance checklists get written that never reach a shop floor.
You cannot spreadsheet people into action.
A supplier is a business with its own margin pressure, its own customers making conflicting demands, and a sustainability contact who has no authority over the operations you need changed. Asking for primary data is asking someone to do unpaid work for a customer who has given them no reason to prioritize it. Escalate that into a mandate and you get what mandates produce without a relationship behind them: a signed commitment letter and a supply chain running the way it ran last year.
The expertise you are not asking about
Somewhere in your supply base is a supplier who already solved a piece of this. They cut packaging waste, or found a material swap that came in cheaper, or took days out of a lead time and reduced emissions as a side effect.
Fifty other suppliers will never hear about it.
Success lives inside one relationship. Your procurement lead knows. The account manager knows. Nothing exists to surface it, write it down or pass it on, and the supplier does not realize it is valuable to anyone else, because they solved their problem and moved on.
The question you send them is not looking for it either. You ask what is your carbon footprint. You do not ask what is working in your operations that others could learn from.
The question determines what you discover. Scope 3 language came out of regulation, it does not match what suppliers do every day, and it hides how many of them are ahead of you on the practice and behind you only on the vocabulary.
What actually moves suppliers
Acknowledge the workload before you add to it. New requirements land on people already stretched, often after a run of other industry changes. A specific thank you, with their actual accomplishments in it, does more than a deck about your targets. It also tells you what else is on their plate, which is what you need in order to prioritize anything.
Put the ones who solved it in front of the ones who have not. Find three to five suppliers with a win worth copying and capture it in their words: a short video, or one page on the problem, the change and what made it work. Then convene eight or ten suppliers and let the successful ones present while the others ask questions. Suppliers learn from people like themselves faster than from an outside expert, and sustainability stops being the one making all the asks.
Make space to design the workflow, not to receive it. Bring suppliers together to design something they will own. People implement what they helped build and work around what was handed to them. Procurement convenes the room. The suppliers do the persuading.
Pay for practice. New practice carries real risk and right now the supplier carries it alone. Give them a window to test at small scale, offset the downside, and let them feel the benefit before you ask for long-term investment. Payments tied to verified action move things that requests never will.
Frame it around their priorities, and connect more than one person. Cost, efficiency, lead time, quality. Show them how the reduction shows up as money saved or rework avoided, and get their operations and finance people talking to yours. A single sustainability contact changes nothing, because the operations you need moved sit elsewhere in their building.
Test the yes. When a supplier agrees to a change, ask how confident they are it will happen by the date, on a scale of one to ten. Under a seven means something is in the way. Resize the step or find out what they are protecting. An untested yes is the most expensive thing in your pipeline.
Ask what you could stop. Somewhere in your process is a request that costs suppliers time and produces nothing anyone uses. Find it and kill it. Removing a pointless ask buys more goodwill than adding a supportive one, and it frees the hours you are about to request.
A six-week reset
Weeks one and two: convene three suppliers who delivered a tangible win and record short show-and-tell clips.
Week three: run one co-design session on a single friction, a packaging swap on your top items or a specification everybody hates. Each site leaves having chosen one practice to test.
Weeks four and five: open a pay-for-practice window with a simple tracker and clear recognition.
Week six: publish a one-page digest. What changed, who led it, what spreads next. Then repeat with the next friction, keeping the proof visible.
What this means for the scope 3 team
Scope 3 teams were built for audit. Carbon accounting, factor selection, boundary logic, assurance readiness. Those are real skills and you still need them, but they describe a supply chain rather than change it.
The skills that move the number are engagement skills. Running a session where suppliers design something together instead of sitting through your deck. Reading which of your top twenty is genuinely stuck and which is quietly refusing. Getting procurement to put it in a contract and finance to fund the trial.
Nobody trained you for that. It was not in the certification and it is not what the platform vendor sells. The Real Change Partner exists for that half of the job.
If your calendar is mostly survey chasing and factor updates, you are running a measurement function for a problem that was never a measurement problem.
Where in your supplier program are you asking for information rather than shifting a daily practice? And which supplier could credibly teach one practical step to three peers this quarter?