Choosing a Digital Marketing Agency: What Most Buyers Get Wrong

Choosing a digital marketing agency is one of the most consequential commercial decisions a marketing leader will make, and most businesses make it badly. They shortlist on reputation, award wins, or a slick credentials deck, then spend the next 12 months wondering why results are thin. The agencies that are best at winning pitches are not always the agencies that are best at running accounts.

This article is about how to buy better. Not how to find an agency that impresses your board, but how to find one that actually moves the commercial needle.

I’ve been on both sides of this. I’ve run agencies, pitched for business, hired agencies as a client, and sat on the other side of the table watching businesses make expensive mistakes. What follows is the framework I’d use if I were a CMO buying agency services today.

Why Most Agency Selection Processes Fail Before They Start

The typical agency selection process is built around the wrong question. Most buyers ask “which agency is best?” when they should be asking “which agency is best for this specific problem, at this specific stage of our business, with this specific budget?”

Those are very different questions. A performance marketing agency with deep expertise in paid search might be exactly right for a business trying to scale ecommerce revenue. That same agency might be completely wrong for a B2B software company trying to build category awareness over 18 months. Context determines fit. And most buyers don’t spend nearly enough time defining their context before they start calling agencies.

When I was running iProspect, we grew from around 20 people to over 100 and moved from loss-making to one of the top five agencies in our space. A lot of that growth came from clients who had already been burned by a previous agency. Not because the previous agency was incompetent, but because the fit was wrong from the start. The client had bought a brand-led agency when they needed a performance-led one, or vice versa. Nobody had done the diagnostic work upfront.

If you want a broader view of the agency landscape before you start shortlisting, the Agency Growth & Sales hub covers the full spectrum of agency models, structures, and commercial considerations.

What Type of Agency Do You Actually Need?

Before you approach a single agency, you need to resolve this question. The answer shapes everything that follows.

There are broadly three models to choose from. A specialist agency focuses on one discipline: SEO, paid media, email, social, or creative. A full-service agency handles multiple disciplines under one roof. And a hybrid model uses a lead agency plus specialist partners for specific channels.

If you’re not sure what a full-service marketing agency actually means in practice, it’s worth reading up before you commit. The term gets used loosely, and what one agency means by “full service” can be very different from another’s version. Some genuinely have deep in-house capability across every discipline. Others have a core team and subcontract heavily, which isn’t necessarily a problem, but you should know which you’re dealing with.

My general view: specialisation beats breadth for most businesses below enterprise scale. If you’re spending £500k a year on digital marketing, you’re better off with a focused agency that truly owns two or three channels than a generalist spreading your budget across six with mediocre results in all of them. The exception is when you genuinely need integrated strategy and the coordination overhead of managing multiple specialists would be too high.

How to Define Your Brief Before You Shortlist

A vague brief produces vague proposals. If you go to market with “we need help with our digital marketing,” you’ll get back a range of proposals that are impossible to compare and none of which will be exactly right.

Your brief should answer five questions clearly:

• What is the commercial problem you’re trying to solve? Not “increase brand awareness” but “we need to generate 200 qualified leads per month at a cost per lead below £80.”
• What channels are in scope? Be specific. If you already run paid search in-house and you need help with SEO and content, say so.
• What does success look like at 6 months and 12 months? Agencies that can’t connect their work to your business metrics are the wrong agencies.
• What is the budget? I know most buyers are reluctant to share this, but withholding budget information doesn’t protect you. It just means agencies guess, and they’ll usually guess wrong.
• What does the engagement model look like? Are you looking for a retained partner, a project-based relationship, or something else?

If you’re running a formal procurement process, a well-constructed RFP for digital marketing services is worth the effort. Most buyers either skip the RFP entirely or produce one so generic it generates useless responses. A good RFP forces you to think clearly about what you need before you ask agencies to respond to it. That clarity alone is valuable.

The Shortlisting Criteria That Actually Matter

Once your brief is tight, you can shortlist properly. consider this I’d weight heavily and what I’d treat with scepticism.

Weight heavily:

Relevant sector experience. Not just “we’ve worked in B2B” but specific experience with your type of buyer, your sales cycle length, your margin structure. An agency that has run campaigns for a SaaS business with a 90-day sales cycle will think differently about attribution and channel mix than one that has only worked in ecommerce.

The actual team. This is the one that catches buyers out most often. The people who pitch you are almost never the people who work your account. Ask directly: who will be the day-to-day account lead? What’s their experience level? Can you meet them before you sign? If an agency is evasive about this, that tells you something.

Commercial fluency. Can the agency talk about your business in revenue terms, not just marketing metrics? An agency that presents proposals in impressions and engagement rates when your business runs on pipeline and margin is not commercially aligned with you. That misalignment rarely improves after you sign.

References from similar clients. Not testimonials on their website. Actual conversations with clients who are similar to you in size, sector, and challenge. Ask the reference specifically: did the agency deliver what they promised in the pitch? What would they do differently?

Treat with scepticism:

Award wins. I’ve judged the Effie Awards and I have enormous respect for the rigour of the process. But award-winning work is selected for its craft and effectiveness in specific contexts. It doesn’t tell you whether an agency will run your mid-market B2B paid search account well. Awards are a signal of capability, not a guarantee of fit.

Impressive client logos. The fact that an agency once worked with a Fortune 500 brand tells you almost nothing about what they’ll do for you. What was the scope of that engagement? Was it a £50k project or a £2m retainer? Who ran it?

Scoping the Engagement Model Before You Commit

How you structure the commercial relationship matters as much as which agency you choose. There are a few models worth understanding.

A retainer model gives you predictable monthly resource and cost. It works well when you have ongoing needs across multiple channels and want a partner who builds context over time. If you’re considering this route, understanding how an inbound marketing retainer is typically structured will help you negotiate a fair deal and set realistic expectations on both sides.

A project model works when you have a defined scope with a clear deliverable and end date. A website build, a campaign launch, an audit. The risk with project work is that agencies have less incentive to invest in understanding your business deeply when the relationship has a fixed end point.

A performance-based model, where agency fees are tied to results, sounds appealing but comes with real complications. Attribution is rarely clean enough to make performance fees fair to both parties. I’ve seen these arrangements create perverse incentives where agencies optimise for the metric that drives their fee rather than the metric that actually matters to the business. Tread carefully.

One thing most buyers underestimate is the internal cost of managing an agency relationship. There’s a reason some businesses choose to outsource social media marketing entirely rather than keep it partially in-house. Splitting ownership of a channel between an internal team and an external agency creates ambiguity about who is responsible for what, and ambiguity is where results go to die.

The Questions Most Buyers Don’t Ask in the Pitch

The pitch process is where most buyers go passive. They let the agency present, they ask a few polite questions, and they make a decision based largely on which team they liked most in the room. That’s not buying. That’s being sold to.

Here are the questions I’d ask in every pitch meeting:

“What would you not do with our budget?” This is more revealing than asking what they would do. An agency that can articulate clearly what they’d deprioritise and why has thought seriously about your problem. An agency that says they’d do everything is either not being honest or doesn’t have a point of view.

“What has gone wrong with a similar client and what did you do about it?” Every agency has had things go wrong. The ones worth working with can talk about it clearly and tell you what they learned. The ones who claim everything always goes well are the ones to avoid.

“How do you handle disagreements with clients about strategy?” You want an agency that will push back when they think you’re wrong. An agency that just executes whatever you ask is a production house, not a strategic partner.

“What does your reporting look like and how does it connect to our commercial goals?” Ask them to show you an example report from a current client (redacted). If the report is full of vanity metrics with no clear line to business outcomes, that’s what you’ll get.

Early in my career, I learned that the best operators are the ones who say no to things. I once taught myself to code because a managing director wouldn’t give me budget for a new website. That instinct to find a way through a constraint is what separates good agencies from average ones. When I’m evaluating agency teams, I’m looking for that same resourcefulness. Do they solve problems, or do they manage them?

Sector-Specific Considerations Worth Knowing

Different sectors have different agency requirements, and it’s worth being specific about this.

If you’re in professional services or recruitment, the marketing challenge is often about building trust and demonstrating expertise over a long sales cycle. The tactics that work for ecommerce brands, high-volume paid social and aggressive retargeting, often perform poorly in these categories. Businesses in the staffing space, for example, face a particular challenge in that they need to market to two audiences simultaneously: clients and candidates. Understanding marketing for staffing agencies as a distinct discipline matters when you’re evaluating whether an agency has genuinely relevant experience or is just claiming transferable skills.

If you’re in a regulated sector, financial services, healthcare, legal, you need an agency that understands compliance constraints. Not one that will learn them on your budget.

If you’re in B2B with a complex product and a long sales cycle, be wary of agencies whose primary experience is in B2C. The metrics are different, the content strategy is different, and the relationship between marketing activity and revenue is harder to trace. An agency that has only ever worked in short-cycle, high-volume environments will default to the wrong playbook.

The Commercial Due Diligence Most Buyers Skip

Before you sign a contract, do some basic commercial due diligence on the agency itself. This sounds obvious. Most buyers don’t do it.

Check their financials if they’re a limited company. Are they growing or contracting? A shrinking agency is often a signal of client churn, which is a signal of delivery problems. Are they profitable? An agency running on thin margins has less capacity to invest in talent and tooling than one with a healthy P&L.

Understanding how accounting works in a marketing agency context gives you a useful lens here. Agency finances have some specific characteristics, particularly around how revenue is recognised and how staff costs are structured, that affect how you should read their numbers. An agency that books media spend as revenue, for example, will look much bigger than it actually is in terms of its own capability.

Ask about staff turnover. High turnover at account management level is one of the clearest warning signs in agency due diligence. If the people who understand your account keep leaving, continuity of knowledge breaks down and your results suffer. Some agencies are very good at hiding this behind confident-sounding new faces in every meeting.

Ask about their technology stack. The range of services a digital agency can offer has expanded significantly, and the best agencies have invested in tooling that makes their work faster and more precise. But technology is only as useful as the people using it. An agency with access to every major platform and tool but junior staff running the accounts is not a good trade.

How to Structure the First 90 Days

The onboarding period is where most agency relationships either build momentum or quietly begin to fail. Most clients are too passive in this phase. They hand over access credentials and wait for the agency to produce something.

A better approach is to treat the first 90 days as a structured test. Agree on specific deliverables and milestones before the engagement starts. What will the agency produce in weeks one to four? What will they have learned and acted on by week eight? What will you review together at the 90-day mark to decide whether the relationship is working?

I’ve seen the paid search model work at its best when the setup phase is taken seriously. When I was at lastminute.com, we launched a paid search campaign for a music festival that generated six figures in revenue within roughly 24 hours. That wasn’t luck. It was the result of precise audience thinking, tight creative, and a landing page that was built around conversion rather than brand. The agency that helped execute it had done the diagnostic work properly in the weeks before launch. The results looked fast because the preparation had been thorough.

The same principle applies to any agency engagement. Fast results in month three are usually the product of good work in months one and two. If an agency can’t tell you clearly what they’re doing in the first 30 days and why, that’s a problem.

For more on how to evaluate agencies across different models and structures, the Agency Growth & Sales section covers the commercial and operational dimensions of agency relationships in detail.

There’s also useful context in how agencies think about their own operations. Resources like Semrush’s breakdown of SEO freelancer versus agency models and Moz’s perspective on the same question are worth reading if you’re deciding between a boutique specialist and a larger agency setup. The considerations on the buy side mirror those on the supply side more closely than most buyers realise.

Social media management is one area where the freelancer versus agency question comes up frequently. Later’s comparison of agencies and freelancers for social is a practical reference if you’re weighing up the options for that specific channel.

The Contract and Commercials

Read the contract. This sounds obvious. A surprising number of senior marketers sign agency contracts without reading them carefully, then discover six months later that they’re locked in for 12 months with a 90-day notice period and no performance exit clause.

The things to look for: minimum term and notice period, what happens to your data and creative assets if you leave, whether media spend is included in the fee or billed separately, how scope creep is handled, and what the escalation process is if performance falls below agreed benchmarks.

A reasonable agency will not object to a performance review clause at the six-month mark. If an agency resists this, ask yourself why. Confidence in your own work means you’re not afraid of being evaluated against it.

On pricing: don’t select on price. Select on value. A cheap agency that delivers poor results is far more expensive than a well-priced agency that delivers strong ones, once you factor in the cost of switching, the time lost, and the opportunity cost of the months you spent not growing. I’ve seen businesses spend more money trying to fix the consequences of a bad agency choice than they would have spent on a better agency in the first place.

About the Author

Keith Lacy is a marketing strategist and former agency CEO with 20+ years of experience across agency leadership, performance marketing, and commercial strategy. He writes The Marketing Juice to cut through the noise and share what works.

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