Facebook advertisers take note – Facebook has today announced that it’s changing the way it displays estimated audience reach for ads, by switching from more specific reach estimates to generalized potential reach categories.

Right now, when you go to set up your Facebook ad, Facebook will display ‘Potential Reach’ with a fairly specific number range of people that your campaign is likely to be seen by, based on the targeting criteria that you select.

Now, Facebook’s scaling that back:

“In order to make the presentation of those pre-campaign estimates consistent, we are changing Potential Reach and interests into ranges instead of specific numbers, which is how Estimated Daily Results are already presented. Ranges are also in line with how pre-campaign estimates are presented on other platforms across the advertising industry. As part of this update, we will also be changing the name of Potential Reach to Estimated Audience Size.”

As you can see here, the new Estimated Audience display is more broad, with the potential reach figure in this example covering a potential discrepancy of 10 million users. Not all of the estimates will be that broad, but the basic premise is the same – Facebook will now show you a much more generalized reach estimate, as opposed to specific numbers, based on your targeting criteria.

The new display will be used for ‘Potential Reach’, ‘Estimated Daily Results’, and for interest categories in estimating the number of people who may have a particular interest.

So why the change?

Facebook doesn’t spell out exactly why it’s updating its numbers, but it does provide some hint of an explanation in the Help Center overview of its Estimated Audience Size calculation:

“Estimated audience size is not a proxy for monthly or daily active users on Facebook, or engagement. (Facebook's quarterly earnings announcements provide this information.) Estimates aren't designed to match population, census estimates or other sources.”

Facebook usage stats are often sourced from these estimates, as a proxy for region specific numbers or insight on people interested in a certain topic, or maybe those who fall into a certain demographic category. Maybe Facebook’s simply trying to avoid misinterpretation by eliminating the use of these figures to incorrectly peg such data points.

It’s also possible that the numbers could be impacted by Apple’s recent changes to in-app data tracking, though for the most part, the figures used in this context come direct from Facebook, so they wouldn’t be impacted by that change.

Either way, it’s another element to consider in your Facebook ads approach – while this point of explanation as to how it estimates potential reach is also interesting:

“In cases where a person has connected their Facebook and Instagram accounts in Accounts Center, their Facebook and Instagram accounts will be counted collectively as a single account for ads estimation purposes. If a person has not connected their Facebook and Instagram accounts in Accounts Center, their accounts will be counted as multiple accounts for ads estimation purposes.”

That could have a significant impact on ad reach data, and may be another reason why Facebook is moving away from more specific figures, and towards more generalized estimates.

You can read more about Facebook’s Estimated Audience Size calculations here.