Google Analytics Sampling despite low sessions

Question

I'm using Google Analytics Reporting API but I get sampled results even though the sessions in the specified date range are much less than the 500K limit. I have only ~4K sessions in a month.

I have also set "samplingLevel" as "LARGE".

Here's the Python query:

    response=analytics.reports().batchGet(
  body={
    "reportRequests":[
    {
      "viewId":myViewID,
      "dateRanges":[
        {
          "startDate":"2017-05-01",
          "endDate":"2017-05-30"
        }],
    "samplingLevel":"LARGE",
      "metrics":[
        {
          "expression":"ga:sessions"
        }],
      "dimensions": [
        {
          "name":"ga:browser"

        },
        {
          "name":"ga:city",
        }
        ]
      }]
  }
).execute()

As you can see below the sample space is 4365 sessions, much lesser than the 500K limit

response.get('reports', [])[0].get('data',[]).get('samplesReadCounts',[])
Out[31]: [u'2051']

response.get('reports', [])[0].get('data',[]).get('samplingSpaceSizes',[])
Out[32]: [u'4365']

Breaking the request into a smaller date range doesn't help either. I tried this using the GoogleAnalyticsR library in R with anti_sample=TRUE.

    > web_data <- google_analytics_4(view_id, 
+                                 date_range = c("2017-05-01", "2017-05-30"),
+                                 dimensions = c("city","browser"),
+                                 metrics = c("hits"),
+                                samplingLevel="LARGE",
+                                 anti_sample = TRUE)
2017-06-04 11:54:51> anti_sample set to TRUE. Mitigating sampling via multiple API calls.
2017-06-04 11:54:51> Finding how much sampling in data request...
2017-06-04 11:54:52> Downloaded [10] rows from a total of [15].
2017-06-04 11:54:52> Data is sampled, based on 47% of sessions.
2017-06-04 11:54:52> Finding number of sessions for anti-sample calculations...
2017-06-04 11:54:53> Downloaded [30] rows from a total of [30].
2017-06-04 11:54:53> Calculated [3] batches are needed to download approx. [18] rows unsampled.
2017-06-04 11:54:53> Anti-sample call covering 14 days: 2017-05-01, 2017-05-14
2017-06-04 11:54:54> Downloaded [7] rows from a total of [7].
2017-06-04 11:54:54> Data is sampled, based on 53.2% of sessions.
2017-06-04 11:54:54> Anti-sampling failed
2017-06-04 11:54:54> Anti-sample call covering 9 days: 2017-05-15, 2017-05-23
2017-06-04 11:54:54> Downloaded [4] rows from a total of [4].
2017-06-04 11:54:54> Data is sampled, based on 55.7% of sessions.
2017-06-04 11:54:54> Anti-sampling failed
2017-06-04 11:54:54> Anti-sample call covering 7 days: 2017-05-24, 2017-05-30
2017-06-04 11:54:55> Downloaded [10] rows from a total of [10].
2017-06-04 11:54:55> Data is sampled, based on 52.3% of sessions.
2017-06-04 11:54:55> Anti-sampling failed
Joining, by = c("city", "browser")
Joining, by = c("city", "browser")
2017-06-04 11:54:55> Finished unsampled data request, total rows [13]

When I check for the same data in a custom request, I see similar sampling

Custom report snapshot

Any idea why I get sampled results even thought the session count is much less than the limit?

I've got a similar problem: Since the beginning of June I only get sampled results when querying totalEvents by pagePath. Even when asking for only one day! The property does not have more than a few thousand sessions. But the hits are generated by Measurement Protocol. Maybe that's the reason. Last month I've fetched correct data. — JerryWho

JerryWho JerryWho · Accepted Answer · 2017-06-20T16:31:02

There's a ticket at Google about sampling despite low sessions at https://issuetracker.google.com/issues/62525952

Google Analytics Sampling despite low sessions

3 Answers