Why Most Media Plans Fail Before the First Ad Runs

13/03/26 // Media Strategy

Written by: Simon

Most conversations about media effectiveness focus on what happens after a campaign launches. The creative, the targeting, the optimisation. But the decisions that determine whether a campaign succeeds or wastes money are usually made weeks earlier, during the planning stage.

Poor briefs, disconnected channel logic, missing measurement frameworks, and budget allocations based on last year’s spreadsheet rather than this year’s opportunity. These are not execution failures. They are planning failures. And they are far more common than most marketing teams would like to admit.

According to WARC’s Future of Measurement report, only 2% of marketers use a comprehensive measurement approach that combines marketing mix modelling, experiments, and attribution. A further 22% use no modelling at all. Most media plans are being built, approved, and launched without a clear way to understand what is actually working.

If you are responsible for a media budget, the five mistakes below are the ones most likely to cost you money before your campaign even starts.

1. Planning brand and performance in separate conversations

Of all the structural errors in media planning, this one is the most persistent. Brand activity gets planned by one team (or one agency), with awareness and reach objectives. Performance activity gets planned by another, with cost per acquisition targets. Both plans are approved separately, measured separately, and optimised separately.

In practice, they are not separate. Brand activity builds mental availability and generates demand. Performance activity captures that demand at the point of search or purchase. Cut brand investment and your performance channels become less efficient over time, because there is less demand to capture. Over-invest in performance without brand support and you end up competing on price in an increasingly expensive auction.

Les Binet and Peter Field’s research on the balance between brand building and sales activation remains the most cited framework here. Their recommended 60:40 split (brand to activation) is a useful starting point, though the exact ratio varies by category and business model. For B2B businesses, updated research suggests closer to 50:50. What matters more than the ratio itself is that both are planned together, with a shared commercial objective.

An ISBA and Ebiquity study found that 37% of UK marketers plan to increase their share of brand advertising in 2026, compared to just 14% who plan to increase performance spend. So the strategic intent is shifting. But in many organisations, planning processes have not caught up. Brand and performance still live in separate briefs, separate dashboards, and separate budget conversations.

A connected approach means building one plan with one set of commercial objectives, then measuring the contribution of both brand and performance activity against those objectives. In practice, that requires a planning partner who thinks across the full funnel rather than specialising in a single channel.

2. Measuring channels in isolation

Every media platform reports its own performance. Google Ads tells you what Google Ads did. Meta tells you what Meta did. Each platform’s reporting is designed to present its own contribution in the best possible light, using different attribution windows, methodologies, and definitions of a conversion.

Add up the conversions claimed by every platform and the total will almost certainly exceed your actual sales. Not because anyone is lying, but because each platform credits itself for conversions that were influenced by multiple touchpoints simultaneously.

Last-click attribution compounds the distortion. By assigning all credit to the final touchpoint before conversion, it systematically over-credits channels that sit at the bottom of the funnel, particularly branded search and retargeting. Upper-funnel channels that generated the initial awareness or consideration receive no credit at all, making them appear ineffective when they may be driving the majority of long-term revenue.

Consider a customer who sees a video ad on YouTube, later reads a blog post, clicks a social ad to browse products, and then converts via a branded Google search. Under last-click, paid search receives 100% of the credit. Video, content, and social receive nothing. Scale that logic across an entire media plan and the inevitable conclusion is “spend more on search, cut everything else”. Over time, that erodes the pipeline of demand that search exists to capture.

According to WARC’s Voice of the Marketer 2025 report, only 45% of marketers use econometrics or marketing mix modelling. More than half are relying on platform-level reporting and basic attribution to make budget decisions. A method that favours channels that are easiest to measure rather than channels that are most effective.

Media fragmentation compounds the issue. WARC data from 2025 shows that 44% of marketers globally cite fragmentation as a top concern. With audiences spread across more platforms, devices, and formats than ever, understanding the interplay between channels requires a measurement framework that sits above any individual platform.

A practical answer involves combining approaches: marketing mix modelling to understand the relative contribution of each channel, attribution modelling to understand the customer journey, and controlled experiments to test causation. Very few organisations use all three. But adopting even one of these approaches is a significant improvement over relying solely on what each platform tells you about itself.

3. Allocating budget by habit, not evidence

Budget allocation is one of the most consequential decisions in media planning, and one of the least scrutinised. In many organisations, next year’s media budget is built by adjusting last year’s figures. Channels that received investment last year receive a similar amount this year, perhaps with a small percentage increase or decrease based on overall spend changes.

Two critical factors get ignored in that approach. First, channel effectiveness changes over time. A channel that delivered strong returns 18 months ago may now be experiencing diminishing returns due to competitive saturation, audience shifts, or rising costs. Second, new opportunities emerge that did not exist in the previous plan. Retail media, connected TV, and attention-based buying models are all reshaping how budgets should be distributed in 2026.

A survey of UK retail marketing decision-makers found that 37% of their digital ad spend, averaging £19,000 per month, goes to channels that are not delivering measurable results. Over a year, that accumulates to £228,000 of budget directed by habit rather than evidence.

Smarter allocation starts with scenario planning. Before committing budget, model the likely outcomes of different strategies. What happens if you shift 15% of search budget into video? What does the saturation curve look like for your highest-spending channel? At what point does incremental spend stop delivering incremental revenue?

Answering these questions requires data and modelling capability. But the cost of not asking them is significantly higher than the cost of building the analytical framework. When your media planning process does not include a scenario planning stage, the budget allocation is essentially a guess informed by precedent.

4. No measurement framework before launch

A surprising number of media plans are approved and launched without a clear measurement framework in place. Briefs specify a target audience and a budget. They may include high-level KPIs like reach or impressions. But they rarely define what a successful commercial outcome looks like, how it will be measured, or what baseline it will be compared against.

Without a pre-defined framework, evaluation becomes a retrospective exercise in finding metrics that look positive. Impressions are high? Good. Click-through rate is above benchmark? Good. But none of these answer the question that matters: did this campaign contribute to commercial growth, and by how much?

Activity metrics (impressions, clicks, video views) tell you what happened in the media. Commercial metrics (cost per acquisition, revenue per order, pipeline value, market share movement) tell you what happened in the business. A media plan should be measured against both, but commercial metrics should drive strategic decisions.

Metric type	Example	What it tells you
Activity	Impressions, clicks, video views	What happened in the media
Efficiency	CPC, CPM, cost per view	How efficiently budget was spent
Commercial	CPA, revenue per order, pipeline value	What happened in the business
Strategic	Market share, brand consideration, LTV	Whether strategy is working long-term

Defining the measurement framework before launch also forces clarity on objectives. When you cannot articulate what success looks like before spending, the plan is not ready. Not because more thinking is needed, but because the money you are about to spend cannot be connected to a result you care about.

5. A brief that does not connect media to a commercial outcome

Every plan starts with a brief. When that brief is superficial, the plan that follows will be too. Academic research from Bournemouth University into media planning practice found that planners regularly cite frustration with briefs that lack essential context: no competitive landscape, no historic performance data, no clear articulation of what the business is trying to achieve beyond “more leads” or “increase awareness”.

A brief that says “we want to reach 25-45 year olds with a £200,000 budget” is not a strategy. It is a set of constraints. A useful brief connects media activity to a commercial objective: what business outcome are we trying to influence, by how much, over what timeframe, and how will we know whether media contributed to it?

Strong briefs contain five elements:

Commercial objective. Not a media objective, but a business one. Revenue target, market share goal, customer acquisition volume.
Audience insight. Beyond demographics. What does this audience care about? Where do they spend attention? What drives their purchase decision?
Measurement framework. Agreed before the plan is built, not bolted on afterwards.
Competitive context. Who else is competing for this audience’s attention, and what are they spending?
Realistic timeline. Brand effects take months to build. Plans evaluated after four weeks will only show activation metrics moving.

Briefs that contain these elements produce sharper plans, give the agency genuine strategic latitude, and create evaluations that are meaningful rather than cosmetic. Without them, the resulting media plan is harder to optimise and easier to waste money on.

How to fix the planning stage

All five mistakes above share a common cause: a planning process that treats media as an execution task rather than a strategic one. Briefs are thin because the planning stage is rushed. Channels are measured in isolation because no one has invested in cross-channel measurement. Budget allocation follows precedent because the analytical framework to challenge it does not exist.

Fixing this does not require a larger budget. It requires a different sequence of decisions:

Define the commercial objective before selecting channels.
Build the measurement framework before approving the plan.
Model budget scenarios before committing spend.
Plan brand and performance together, not separately.
Evaluate media against business outcomes, not platform metrics.

These steps separate media plans that deliver growth from media plans that generate activity reports. Not by spending more, but by thinking more carefully about why and where the money goes before it is spent.

When the planning stage gets this right, optimisation during the campaign becomes genuinely productive. You are refining a strategy that has clear objectives, a measurement baseline, and a commercial logic connecting spend to outcome. When it does not, you are adjusting dials on a machine that was never calibrated to begin with.

We help brands build media plans that start with commercial clarity, not channel tactics. Talk to our team about how consultancy-led planning works in practice.

Frequently asked questions

What is the most common media planning mistake?

Planning brand-building and performance activity separately. When both are disconnected, brands tend to over-invest in demand capture and under-invest in demand creation, which reduces overall media efficiency over time.

How do you measure media plan effectiveness?

Robust measurement combines three methods: marketing mix modelling to understand channel contribution, attribution modelling to map the customer journey, and controlled experiments to test causation. According to WARC, only 2% of marketers currently use all three.

What is the difference between media planning and media buying?

Media planning is the strategic stage: defining objectives, selecting channels, allocating budget, and building the measurement framework. Media buying is the execution stage: negotiating rates, placing ads, and optimising delivery. Planning determines what to do and why. Buying determines how and at what cost.

How should brands split budget between brand and performance?

Binet and Field’s research suggests approximately 60% brand and 40% activation for most consumer categories, though this varies. B2B brands may benefit from closer to 50:50. More important than the exact ratio is that both are planned and measured as parts of one commercial strategy.

What should a media brief include?

A strong media brief includes: a commercial objective (not just a media one), audience insight beyond demographics, a pre-agreed measurement framework, competitive context, and a realistic timeline for results. Briefs that lack these elements typically produce plans that are harder to evaluate and easier to waste money on.

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