Why unique user counts differ across breakdowns
Why does summing unique users by day give a higher number than the total?
Section titled “Why does summing unique users by day give a higher number than the total?”Each breakdown counts a user once per group, not once per period.
A user who visits on Monday, Wednesday, and Friday appears in 3 daily rows. That same user counts as 1 in the total for the period. Sum the daily rows and you get 3. The total says 1. Both are correct.
Is this a data error?
Section titled “Is this a data error?”No. It is expected behavior.
Total unique users deduplicates across the entire period. Each user is counted once, regardless of how many days, authors, or cities they appear in.
Breakdown unique users deduplicates within each group only. The same user can appear in multiple rows.
| Breakdown | What happens |
|---|---|
| By day | A user active on 3 days contributes 1 to each daily row, 1 to the total. |
| By author | A user who reads 4 authors contributes 1 to each author row, 1 to the total. |
| By city | A user accessing from 2 cities contributes 1 to each city row, 1 to the total. |
How do I get an accurate unique user count?
Section titled “How do I get an accurate unique user count?”Use the total unique users metric directly over your selected date range. Do not sum values from breakdown rows. The sum will always exceed the real total.