As the digital advertising sphere continues to flourish, measuring the right metrics matters more than ever. But just as the platforms continue to grow multi-faceted and cluttered, so too do the metrics a digital advertiser must understand to measure ROI (return on investment). This is no truer than with the often confusing and wrongly interchangeable metrics: Reach and Impressions. Marketers toss these terms in the air too often without fully grasping the difference and distinction between them. So rather than allowing you, dear reader, to be in the position of being too afraid to ask, let's address the difference (and similarities) today.
What Is Reach?
Reach measures the unique number of people who see your content on social channels, chiefly Facebook and Instagram. Reach specifically counts the true number of people reached with your content. Reach does not discriminate across devices either. If you serve an individual viewer an ad on their phone, iPad, and laptop, the reach for that viewer will still only count as one.
Reach doesn't care how many times an ad was seen; reach only measures the number of people who saw it.
Then What Is an Impression?
In contrast, we use the Impression metric to measure the total number of times an ad has been seen. Unlike Reach, Impressions count every single time an ad was seen, regardless of the people doing the seeing. Essentially, figuring out how many times content hits a unique person’s feed is what Impressions are handy for. So, say a Facebook ad displayed 400 times and the reach was 250, the impression count would be 400. Whether that ad was seen on one device, or seen on multiple devices, each time the ad appeared, anywhere, counts as an Impression.
The Perfect Pair
Both of these metrics provide necessary information to determine the success (or failure) of a specific ad or entire campaign. So when should you use one over the other?
Reach serves you better if the goal is to get your content out to the masses. The larger the Reach, the larger your penetration into a given market.
Impressions, on the other hand, serve you better when you're looking to increase the frequency and make an impact. Serving an ad only one time to an individual may not have the "staying" power you're looking for. In that case, you'd want to increase your Impressions over a limited Reach to increase the frequency of your ad.
So, remember, one is not exclusively better than the other. Both reach and impressions analyze different things and are important metrics on their own.