Google Analytics Data Sampling: Why it Matters


Google Analytics is the most popular analytics tool on the market for web traffic analysis. Unfortunately, a number of Google Analytics users come across precision issues related to data sampling, among other privacy concerns. This is relevant to those with small and large traffic. The data sampling takes place when a free user reaches 500,000 sessions and a premium user (Google Analytics 360) reaches 100M sessions for the month.

Despite the fact that Analytics 360 is priced at $150,000 per year, Google still uses data sampling, which reduces the accuracy of the data.

How do you know if your data is being sampled?

You can identify if you data is being sampled by looking at the top right corner of your Google Analytics report. If that is the case, you would see a yellow rectangular, which will tell you what number of sessions is your report based upon.

Google Analytics data sampling example

What is Data Sampling?

Google describes data sampling in their own help docs as follows: “In data analysis, sampling is the practice of analyzing a subset of all data in order to uncover the meaningful information in the larger data set.”

It is essentially implying that instead of analyzing the entire data set, Google takes a small subset of the data (depending on your plan) and assumes what the real data should look like.

This practice is fine, when analyzing very large data sets, however the accuracy of the report goes out of window if you sample size is based on 10% or less of your total sessions. Imagine paying $150,000 per year to get a report that is essentially useless.

Why is Data Sampling so Bad?

Two major reasons behind it are:

  1. When the sample size is very small, it will generate an erroneous report that is not a representation of the actual data
  2. The more visitors you get, the less accurate your reports become

As we saw, data sampling occurs on GA’s free plans, as well as paid plans. When you look at your web site traffic reports, it is based on some sample number, but does not reflect the entire data. This could lead to making inaccurate inferences about your web site’s growth and evolution, it could have an impact on how you spend money on ADs and more.

With PrivateAnalytix, we do perform data sampling, and the reports are based 100% on the data that has been collected. We also give you 100% ownership of your data and respect your visitor’s privacy.

What are Real-Life Examples why Data Sampling is Bad?


For eCommerce web site owners, it is common to see that the sales numbers do not exactly match with the traffic data. This could create the wrong assumption about the ROI. The ROI is normally calculated in Facebook ADs and the one calculated in Google Adwords is based on data sampling.

So, this begs a question. Why use Google Analytics is you can get your ROI data from Facebook? And how accurate is the actual ROI that you get from your Google Adwords report?

Bloggers/ Affiliate Marketers

Imagine seeing an annual Google Analytics sales report that shows $200,000, where the actual number is much lower ($125,000). This is a direct result of sampling, where the sales figures have been extrapolated. That might lead you to make the wrong decisions about profitability, AD spend future budget allocation.

Both of the above owners might be missing vital opportunities, because of the extrapolated data.

The bottom line is that, the larger your web site/business becomes, the less you can trust this risky data patter analysis strategy to make business decisions.

What are the Benefits of 100% Accurate Data?

PrivateAnalytix does not infer or use sampling of your web site traffic data. you get a report that is 100% based on the information our pixel collected from your web site. It will be much easier for you to make strategic decisions knowing that what you see is what you had.

Here are some reasons why PrivateAnalytix lack of data sampling will benefit you:

  1. Make appropriate strategic decisions
  2. Accurate inference of your sales vs traffic
  3. Never miss actual trends to data inference
  4. Accurate ROI calculation is possible

Among many other benefits, PrivateAnalytix offers session replays and heatmaps for an affordable cost that grows with your business. We want you to be successful, so we can be successful.

If you are ready for the challenge, give PrivateAnalytix a try for 14 days. It is absolutely free, and we don’t even require a credit card.