Google analytics work fine for small and medium-sized websites, but when the data volume increases, some of the reports are sampled. See in this presentation some of the most common issues and how you can overcome them.

1. Google Analytics sampling
limitations
and how to overcome them
George
Papadongonas
Web
Analyst,
Amazee
Metrics
16/7/2013

2. How Google Analytics stores data
• All unfiltered data of a web property (up to 10 million hits per
month) are stored in the Google Analytics database
• Each standard report has an associated data table in the Google
Analytics database with unsampled data
• Reports for accounts with more than 200,000 visits per day are
processed daily
• Reports for accounts with less than 200,000 visits per day are
processed more often
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3. Google Analytics
Report Sampling
• Sampling starts when the requested date range has more than
500,000 visits
• The sample size can be arranged by using the Google Analytics
sampling slider. The default setting is for 250,000 visits, maximum
setting is 500,000
• Visits are counted for the specific date range on a Web Property level,
not on a Profile level
• Standard reports without filters, advanced segments or secondary
dimensions use always unsampled data
• Sampling applies to custom reports
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4. Organic Search traffic report
is unsampled
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5. By adding a second dimension,
sampling is applied
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6. Adjust the sampling size
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7. Prefer the
higher precision setting
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8. Google Analytics
Report Sampling
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9. How sampling is calculated
• Web property has 24,580,303 visits
• Profile has 492,786 visits
• Default sampling is: 250,000x492,786/24,580,303 = 5,012 visits (1%)
• Maximum sampling is: 500,000x492,786/24,580,303 = 10,024 visits (2%)
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10. Avoid the
faster processing setting
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11. Prefer the
higher precision setting
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12. Pageviews or events reports
can be unreliable
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13. Google Analytics
Report Sampling
• Visits and Visitors reports are usually reliable, even with a small
sample
• E-commerce transactions, individual pageviews, adwords data,
revenue and goal conversions are less reliable
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14. Solutions
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15. 1. Buy Google Analytics Premium
• “Only”$150.000 / year
• 1 Billion hits processed per month
• Unsampled reports
• Data processing every 4 hours
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16. 2. Create custom profiles
• Instead of creating reports with specific advanced segments,
create custom profiles using filters
• The default reports of all profiles are always unsampled, even if the
visitors are more than 500,000
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17. 3. Enable Data Sampling
• Sample your data , by adding a line in the Google Analytics
tracking code
code_gaq.push(['_setSampleRate', '80']); Sets
sampling rate at 80%
• Not a perfect solution, as the data are still sampled, but you have
control and can avoid tracking interruption (for more than 10
million hits per month)
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18. 4. Use smaller date range
• Break you report in smaller data ranges, each one having less than
500.000 visits
• This ensures that the data are unsampled
• Export the reports using the Google Analytics API
• Aggregate the data in Excel and create the master report
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19. 5. Use analyticscanvas.com
• Analytics Canvas offers query partitioning, using the Google
Analytics API.
• Reports are exported in smaller date ranges, so that they are
unsampled and they are then merged automatically with Analytics
Canvas.
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20. 6. Download Google Analytics
data locally
• It is possible to keep a local copy of Google Analytics data
• Add a line in the Google Analytics tracking code
_gaq.push(['_setLocalRemoteServerMode']);
• Add _utm.gif to your web server root
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21. 6. Download Google Analytics
data locally
86.138.209.96 www.mysite.com - [01/Oct/2007:03:34:02 +0100] "GET /__utm.gif?utmwv=1&utmt=var&utmn=
2108116629 HTTP/1.1" 200 35 "http://www.mysite.com/pageX.htm" "Mozilla/4.0 (compatible; MSIE 6.0;
Windows NT 5.1; SV1; .NET CLR 1.1.4322)" "__utma=1.117971038.1175394730.1175394730.1175394730.1;
__utmb=1; __utmc=1; __utmz=1.1175394730.1.1.utmcid=23|utmgclid=CP-Bssq-oIsCFQMrlAodeUThgA|
utmccn=(not+set)|utmcmd=(not+set)|utmctr=looking+for+site; __utmv=1.Section One"
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• Data are recorded in the server log files
• Use http://analytics.angelfishstats.com/ to analyze them, as Urchin is
discontiniued

22. Thanks!
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