A good scenario plan shows three futures: what happens if budget stays flat, what happens if it is cut by 20 percent, and what happens if it grows by 20 percent. Each scenario needs a revenue forecast, not just a spend plan.
Budget planning season produces a lot of spreadsheets with spend by channel. Very few of those spreadsheets show what revenue each scenario is expected to generate. Without that connection, you are presenting a cost plan, not a business plan. This guide explains how to build scenario models that link marketing spend to revenue outcomes.
Why you need three scenarios, not one
Single-point budget plans assume the future is predictable. Presenting one number tells your leadership team you are confident in a figure you cannot possibly know with certainty. Three scenarios signal that you understand the range of outcomes and have thought about how to respond to each. It also protects you: if the business cuts your budget, you have already modelled what happens.
What each scenario should contain
- Total budget and split by channel.
- Projected revenue contribution from marketing (incremental, not total).
- Expected cost per acquisition by channel.
- Projected market share or share of voice where relevant.
- Key assumptions: seasonality, competitor activity, pricing changes.
- Risks and what would need to be true for the scenario to hold.
Building the revenue forecast for each scenario
The revenue forecast is the hardest part and the most important. You need a way to translate spend inputs into revenue outputs. The most reliable method is a Marketing Mix Model, which gives you a response curve per channel. You can then run each spend scenario through the model to project revenue. If you do not have an MMM, use historical data: plot quarterly spend against quarterly revenue per channel and fit a trend line to estimate the relationship.
Be careful about linearity. Do not assume that doubling spend doubles revenue. It rarely does. Your model should reflect the fact that returns diminish as spend increases. If you cannot model diminishing returns, at minimum flag the assumption explicitly so your leadership knows the forecast assumes efficiency holds at higher spend.
The scenario that gets cut from the plan is often the one with no revenue forecast attached to it. Teams that show a minus-20-percent scenario alongside a minus-15-percent revenue impact protect their budgets far more effectively than teams that present spend as a cost.
The cut scenario: showing the true cost
Most budget plans present upside scenarios in detail and gloss over the downside. Flip this. The cut scenario is your most powerful tool. Show specifically which channels would lose budget first (the least efficient ones), what revenue you expect to lose, and over what time horizon. Include the recovery cost: how much extra spend you would need, and for how long, to return to your current trajectory after a cut.
Presenting scenarios to senior leadership
Lead with the flat scenario as the baseline. Show the revenue line, not the spend line. Then show what changes in each alternative scenario: revenue up X, revenue down Y. Frame the growth scenario as an investment case: here is the incremental revenue per additional pound spent. Frame the cut scenario as a risk: here is the revenue we lose per pound removed. Keep the visuals simple. One chart per scenario showing spend and projected revenue is enough.
Updating your scenarios through the year
Scenario plans are not one-and-done. Reforecast quarterly using actual spend and actual sales data. Compare your forecast revenue against what actually happened. The gap between forecast and actual tells you where your model assumptions were wrong and helps you build a more accurate plan for the next period.
How far out should my scenarios forecast?
For annual planning, model 12 months. For strategic planning, extend to 24 months, but flag that accuracy falls sharply beyond 12 months. The purpose of a 24-month view is not precision. It is to show the compounding effect of sustained investment or cuts on brand equity and market share.
What if my MMM or historical data does not cover a specific channel I want to include?
Use industry response curve benchmarks as a starting point and flag them as assumptions. Most MMM vendors publish typical response curve shapes by channel type. Apply the benchmark curve to your planned spend levels and present the revenue projection with a wide confidence interval to reflect the uncertainty.
Our finance team has their own revenue model. Should I align to it or use my own?
Align where you can. Ask your finance team for their baseline revenue forecast and show your marketing contribution as an uplift on top of that baseline. This avoids arguments about whose model is right and positions marketing as additive to the business plan, not a separate forecast.