How to Calculate ROI on an Out of Home Campaign. A step-by-step method for calculating return on a mall or billboard campaign, including the baseline, the math, and the mistakes that produce misleading numbers.
Out of home gets accused of being unmeasurable, usually by people who never set a baseline before the flight started. The measurement problem is almost always a planning problem: nobody wrote down what normal looked like before the ads went up.
This is the method we walk clients through. It works for a single mall placement or a multi-market billboard buy, and it does not require any special software.
Step one: set the baseline before the flight
Pick the outcome that actually matters to the business: store visits, phone calls, form fills, booked appointments, or revenue in the trade area. Then record the previous eight to twelve weeks of that metric so you have a stable pre-campaign average, not a single week that might be an outlier.
Do this before the posting date. A baseline reconstructed after the fact is always contested, because everyone involved has an opinion about which weeks should count.
- Choose one primary outcome metric and at most two secondary ones
- Record eight to twelve weeks of history for each
- Note any known seasonality, promotions, or price changes in that window
Step two: isolate the exposed area
The single biggest source of bad OOH math is measuring business-wide results against a campaign that only ran in one trade area. Split your reporting so exposed locations or exposed ZIP codes are counted separately from everything else.
If you have multiple locations, the unexposed ones become a control group. Any lift that appears in both exposed and unexposed markets was caused by something other than the campaign.
Step three: run the math
Incremental lift is the exposed-period result minus the baseline, adjusted by whatever change the control group showed over the same weeks. Multiply that lift by your average order value and gross margin to get incremental gross profit, then compare it to total campaign cost including production.
The formula is: ROI = (incremental gross profit - total campaign cost) / total campaign cost. Express it as a ratio if that lands better with your stakeholders, but keep production in the cost line either way. Leaving production out is the most common way a mediocre campaign gets reported as a winner.
- Incremental result = exposed lift - control lift
- Incremental gross profit = incremental result x average order value x gross margin
- Total cost = media + production + installation + creative
- ROI = (incremental gross profit - total cost) / total cost
Step four: account for the lag
Out of home builds. A four-week flight rarely shows its full effect within four weeks, particularly for considered purchases such as healthcare, education, financial services, or home improvement. Measure the flight window plus a trailing period of at least four weeks.
This is also why single-flight tests understate performance. If the budget allows only one test, run it for three consecutive flights in one property rather than one flight across three.
Tracking mechanisms worth adding
You can sharpen attribution cheaply with a few mechanisms built into the creative, as long as they do not clutter the design or force the audience to do work they will not do while walking.
- A dedicated tracking phone number used only on the placement
- A short vanity URL that redirects to a landing page with its own analytics
- A QR code sized and placed for a standing reader, not a passing driver
- An in-store prompt asking how the customer heard about you
- Geolocation-based store visit studies for larger multi-market buys
Frequently Asked Questions
Can out of home advertising really be measured?
Yes, provided you set a baseline before the flight and separate exposed markets from unexposed ones. Most measurement failures are planning failures.
How long should I wait before judging results?
Measure the flight window plus at least four trailing weeks. Considered purchases take longer to convert than impulse categories.
Should production costs be included in ROI?
Always. Excluding one-time production is the most common way a campaign looks more profitable on paper than it was.
What is a good ROI for a mall campaign?
It depends entirely on margin. A high-margin service business can justify a campaign at a much lower lift than a low-margin retailer, which is why the math has to use gross profit rather than revenue.
MallAds.com is a division of Sullivan Media, Inc. We have spent more than 20 years placing brands inside America's shopping centers and along the roads that lead to them, with access to advertising in over 1,700 malls plus billboard placements nationwide. Tell us your market, audience, and budget and we will build the plan around them.