Supplier ESG reviews: how can a business start with evidence?

A supplier ESG review starts by identifying business relationships that could create significant impacts on people, the environment and organizational governance. The next step is to request evidence proportionate to the risk and follow up on findings. For a business in Mexico, this can connect purchasing, operations and compliance instead of becoming a questionnaire that has little effect on decisions.

Define what the review needs to establish

ESG covers environmental, social and governance factors. In supplier review, the useful question is how a supplier's activities relate to the company's risks and impacts. Different products, locations and services may call for different levels of scrutiny rather than an identical information request.

OECD guidance offers a due diligence framework for responsible business conduct, including business relationships. Its recommendations inform the identification of issues and appropriate responses; they do not amount to a universal mandatory certification for every Mexican business.

Before designing questions, define the decision being supported: appointing a supplier, renewing a relationship or responding to a particular concern. That purpose determines what information is useful, who should assess it and what would count as an adequate answer.

Select evidence that answers real questions

• Describe the product or service and where the activities relevant to the purchase take place.
• Identify potential environmental, labor or integrity effects associated with the activity, without assuming misconduct.
• Request records connected to priority questions, explaining the period and scope they should cover.
• Distinguish supplier statements, evidence actually reviewed and matters requiring additional verification.
• Agree a channel for clarification and identify who owns each finding within both organizations.
• Define how commitments will be followed up and what changes would trigger another assessment of the relationship.

Evidence needs context. A certificate may apply to one facility or process rather than the whole company. Checking its coverage helps avoid turning an isolated document into a broad conclusion about the supplier. It also makes requests for additional information more precise and easier for the supplier to understand.

Move from a questionnaire to a recorded decision

Imagine a business purchasing warehousing services and receiving general statements about waste management. The review can ask which relevant activities occur and what records exist, rather than repeating a broad sustainability question that produces another general answer.

Where gaps appear, describe them, assess their significance and agree proportionate actions. A follow-up plan should identify owners and evidence of progress. Leaving a box marked pending without further action offers limited information for the next purchasing decision.

The team should also distinguish adequate information, an outstanding clarification and an issue requiring specialist review. This traceability helps explain why a decision was made and which conditions need subsequent attention. Conclusions should be updated when relevant facts change, not only when an administrative review date arrives.

Frequently asked questions

Should every supplier complete the same questionnaire?

A common foundation can simplify administration, but depth and questions should reflect the service, location and potential impact. Requesting irrelevant material increases work without necessarily improving the quality of the decision or the understanding of the relationship.

Does a sustainability policy prove supplier compliance?

A policy communicates commitments, while implementation requires evidence. Review what it covers, who puts it into practice and how outcomes are recorded. Applicable legal obligations need their own assessment based on activity and location.

Next step: prepare a sustainability and ESG discussion with your supplier categories and the decisions you need to support. This guide proposes a review method; it does not certify any company's environmental or social performance.