A marketing supplier should be assessed against the audience, channels and business result you want to achieve. A portfolio can show creative ability, but campaign evidence needs context: the budget, measurement method, market and contribution of other teams all affect the result.
Ask for evidence you can interpret
Request a comparable campaign with its objective, timeframe and reporting definitions. Distinguish impressions and clicks from qualified enquiries, sales and retained customers. Check whether the supplier is reporting platform attribution, analytics data or a reconciled commercial outcome; these measures need not agree.
Review example creative and landing pages alongside the campaign plan. Ask how the team researches the audience, checks claims and responds to weak performance. Establish which work is performed by the proposed team and which requires additional production or development support.
Keep accounts and costs transparent
Clarify ownership and access for advertising accounts, analytics, domains and creative files. Separate agency fees, media spending and third-party costs. Obtain the reporting schedule and an example report that explains decisions as well as results.
Record the limits of any performance claim and the responsibilities for tracking, lead handling and approval. A supplier can influence acquisition while your pricing or sales response affects conversion. Approval should reflect these dependencies rather than turning a past result into a guarantee for your campaign.