6 Foundational OOH Planning Metrics to Know Before You Build Your Plan

A quick guide to the numbers that help you understand your plan's expected exposure, audience, and cost in MW Planner.

A good Out-of-Home (OOH) plan is more than a list of inventory. These 6 metrics help you understand what your plan is expected to deliver and compare different planning options before you submit.

1. Total Impressions

The total number of times your advertisement is expected to be viewed across the selected inventory and campaign period.

• Use it to: Understand overall exposure, compare inventory selections, and check delivery against your campaign goal.
• Remember: Impressions measure total exposure, not unique people.

2. Estimated Reach

The projected number of unique people expected to see your campaign at least once.

• Use it to: Understand potential audience coverage and compare plans based on audience size rather than just impression volume.
• Remember: Reach and Frequency are read together. They are omitted when reach cannot be estimated.

3. Average Frequency

The average number of times a person in the estimated reach is expected to see your campaign.

• Use it to: Understand the balance between audience breadth and repeated exposure. Read it alongside Reach to assess if extra impressions add useful frequency.
• Remember: Frequency is an average, not a guarantee that every person sees the campaign the same number of times.

4. Estimated Ad Plays

The expected number of times your ad will play across applicable inventory during the campaign period.

• Use it to: Understand planned delivery volume and see how schedule adjustments affect delivery.
• Remember: Ad Plays apply to spot-based digital delivery. Classic inventory uses days-based metrics instead.

5. Avg CPM (Average Cost Per Mille)

The impression-weighted rate-card cost per 1,000 impressions for the media in your plan.

(Note: "Mille" is Latin for thousand, so CPM means "Cost Per Thousand Impressions").

• Use it to: Compare quoted media cost efficiency across different inventory options.
• Remember: For impression or reach goals, Planner uses Avg CPM.

For CPS (Cost Per Spot) goals such as Share of Voice (SOV) or Ad Plays, media-plan surfaces show Avg CPS instead.

6. eCPM (Effective Cost Per Thousand Impressions)

The effective cost per 1,000 projected impressions based on the total cost of the plan.

• Use it to: Compare true cost efficiency between plans after total fees and additional plan costs are factored in.
• Remember: eCPM = (Total Cost ÷ Total Impressions) × 1,000.

Unlike Avg CPM (which uses the media owner's quoted rate-card price), eCPM measures your effective cost based on your total plan budget.

Read the Metrics Together

No single metric tells the whole story. Use all 6 together to ensure your plan has the right balance:

• Impressions — How much exposure
• Reach — How many unique people
• Frequency — How often
• Est. Ad Plays — Planned delivery volume
• Avg CPM / Avg CPS — Quoted media rate
• eCPM — Effective plan cost

Before You Submit

Review these metrics in your Plan Summary and ask:

• Does the plan deliver enough against the campaign goal?
• Is the reach and frequency balance right?
• Does the schedule support the intended delivery?
• Does the cost make sense for the expected delivery?

Tip: The strongest plan isn't necessarily the one with the most impressions or the lowest cost. Whenever you adjust inventory or schedules in MW Planner, re-check your Plan Summary — your forecast updates in real time.