Reach is a metric that measures how many individual users have seen your content. You can split reach by dimensions such as posts, campaigns, or time ranges and get separate reach values for these.
However, you can't sum up the reach of, for example, different campaigns. Summing up reach isn't allowed, and trying to sum it up gives you one of the following errors:
- Can’t be calculated, would require summing deduplicated values
- Null
- No data.
If summing up reach was allowed, you'd get a false reach value, as it could count the same user multiple times, and the reach number in your report would be higher than the reach actually was.
For example, imagine there's a user who was reached on January 1 and also on January 2. The reach for both days would be 1. If you sum this up, you'd have a reach value of 2, even though you only reached 1 person. You can't, for example, sum daily campaign data to get the correct reach for campaigns last week.
If you apply filters to your queries, you're also then splitting your data by those rules. If you filter by the campaign name and the filter matches 2 campaigns, a reliable reach value isn't displayed. This is because the reach value of 2 campaigns can't be summed.
This logic applies to all non-summable or deduplicated metrics, such as frequency, sessions, and users. Learn more about how to solve issues with non-summable metrics.
From raw data to visualization
If you're storing data in a data warehouse or raw data in Google Sheets, you need to consider some things when visualizing reach data in, for example, Looker Studio.
You need to decide beforehand what level of detail you want to report, such as weekly or monthly, campaign or ad level. You also need to have separate queries for, for example, weekly data, which you can then show on scorecards.
If you have, for example, daily reach data in Google Sheets, your data won't be correct if you create a scorecard in Looker Studio because the Google Sheets connector will sum up the data for the scorecard.
You might need to exclude some queries from the date selection if you're using a date selector. You can exclude charts from the date selector by selecting a custom date range instead of "Auto". For example, if you query the campaign name and week or month, but don't use full weeks or months, the data doesn't add up.
Google Sheets
You need to have separate queries for each aggregation you're going to use in Looker Studio. For example, you can create a query with “year & week” and “Campaign name” to get weekly data for campaigns.
Data warehouse
For data warehouse products, you can, for example, create a snapshot with "year and week" and "campaign name" to get weekly data for campaigns. You'll have to do this for each aggregation you want to report on.
For any queries that are not at a daily grain, you will need to leave out the Date column and this will cause the query to run in ‘snapshot’ mode. Take a look at this support article to learn more about our refresh options.