Digital Ad Terms Glossary: CPM, CTR and ROAS in Plain Words

Summary: This is a short glossary of the best-known digital advertising terms on Meta, TikTok and Snapchat, such as CPM, CTR, CPA, ROAS, the hook and ad fatigue. Each term has a plain meaning and how it is calculated or when to look at it, so you can read your results dashboard with confidence and know which part of an ad needs work.

What do impressions, reach, frequency and CPM mean?

Impressions are the number of times an ad is shown on screens, reach is the number of different people who saw it, and frequency is how many times one person saw it on average. CPM is the cost of a thousand impressions, and it tells you what you pay to reach the audience before anyone interacts with the ad or buys.

Frequency that rises over time is a sign that the same audience sees the ad many times, and that is one of the first causes of boredom.

What do CTR, CPC and conversion rate mean?

CTR is the click-through rate: how many people clicked the ad out of everyone who saw it. CPC is the cost of a single click, and the conversion rate is the share of people who completed the desired action out of those who clicked. Together these three tell you whether the ad persuades the viewer to take the next step, and whether the store page finishes what the ad started.

If the click-through rate is good and the conversion rate is weak, the problem is usually the product page, the price or the shipping, not the video.

What do CPA, ROAS, CPI and average order value mean?

CPA is the cost of getting one customer or conversion, and ROAS is the return on ad spend: the ad's revenue divided by what was spent on it. CPI applies to apps and is the cost of one install, and the average order value is what a customer pays in one order, which sets how much you can spend to win a customer.

If your product is an app, our app-install ad guide explains weekly video testing and what to measure alongside CPI.

What do the pixel, retargeting and lookalike audiences mean?

The pixel is code placed in your store that tells the platform what a visitor did after the ad, such as adding a product to the cart or completing a purchase. Retargeting means showing the ad to people who visited the store or interacted before, and a lookalike audience is a new audience the platform picks because it behaves like your current customers.

What do the hook, the angle and the call to action mean?

The hook is the opening of the ad that stops the scroll in the first seconds, and the angle is the reason to buy that the ad focuses on, such as a gift, the price or comfort. The call to action is the final line that tells the viewer what to do now. Changing any one of them creates a new version worth testing.

How to build versions from these parts is in the ad testing matrix.

What do ad fatigue and A/B testing mean?

Ad fatigue means the audience has grown tired of an ad after seeing it many times, so its results weaken gradually even though it used to work. An A/B test compares two versions that differ in only one element, such as the opening, to find out which is better. The usual cure for fatigue is to prepare new versions before the current ad weakens.

Why a winning ad declines and how to prepare for it is in Why winning campaigns collapse after 14 days.

What do Hook Rate, Thumbstop and Hold Rate mean?

Hook Rate, which some call Thumbstop, measures how many people watched the first seconds of an ad, often the first 3 seconds, out of everyone it was shown to. Hold Rate measures how many of them kept watching to a later point, such as the middle or the end of the ad. The first judges the opening and the second judges the body, and each platform and report counts them a little differently.

Compare these metrics with your own account average, not with general figures, because the product, audience and platform all change them.

What do Spark Ads, Advantage+ and Smart+ mean?

These are names of ad options inside the platforms. Spark Ads on TikTok promote an ordinary post from a TikTok account as an ad while keeping the engagement on it, Advantage+ on Meta is a set of automated settings that leave the audience and placements to the system, and Smart+ on TikTok is a similar automated campaign. Their details change often, so check the official help pages before relying on them.

The more these campaigns rely on automation, the more it matters to feed them ads that vary in their idea.

What do the 9:16 size and the safe zone mean?

The 9:16 size is the vertical video that fills a phone screen, and it is the standard on TikTok, Snapchat, Reels and YouTube Shorts. The safe zone is the part of the screen not covered by the platform's buttons, account name and caption, so the product and the key text must stay inside it and not disappear behind the interface.

Details of the other sizes are in One ad in every size.

How do you read these metrics together?

Read them in the order of the viewer's journey: first, did people stop at the video, then did they click, then did they buy and at what cost. This order shows exactly where the problem is: a weak opening, a message that does not persuade, or a store page that does not finish the sale. And do not judge an ad on one day or on a small number of impressions.

1. Look at the share of people who watched past the first seconds to judge the hook.
2. Look at the click-through rate to judge the message and the call to action.
3. Compare the cost per acquisition and the return on ad spend to judge profitability.
4. Watch frequency and click-through rate together to spot fatigue early.
5. Change one element in each test so you know what caused the improvement.

How can you try this on your product?

Request a free sample video before any payment. Product photos and a store link are enough, with no sample shipping, and the first batch arrives 48 to 72 hours after script approval, in 9:16 for Meta, TikTok, Snapchat and YouTube Shorts.

Read also: How to Write a Short Ad Video Script

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Read also: Instagram Ads for Stores: Reels and Stories Design

Read also: Snapchat Ad Sizes and Video Specs Guide

Read also: Short Ad Video Editing: What Holds Attention?

Frequently asked questions

What is the difference between CPM and CPC? CPM is the cost of a thousand impressions whether or not anyone clicks, while CPC is the cost of a single click on the ad.

What is the difference between ROAS and ROI? ROAS divides the ad's revenue by its spend only, while ROI measures profit after all costs such as the product, shipping and operations.

Does a higher click-through rate mean more sales? Not always. People may click out of curiosity and not buy, so the click-through rate is read together with the conversion rate and the cost per acquisition.

What is the most important metric for short video ads? There is no single one. Start with the share of people who watched past the first seconds, because it measures the hook, then move on to clicks and purchases.

What does UGC mean in advertising? UGC means content in the style of ordinary users, and the full explanation is in What is UGC?.

Part of our approach to Scaling Ad Creative from 30 to 200 Videos per Month.