This document provides an introduction to Google Analytics for web developers. It discusses how Google Analytics can be used to track and understand visitor traffic, flows, and engagement on a website. It also describes how the Google Analytics tracking code works to collect anonymous visitor data and send it to Google's servers. Finally, it covers some key aspects of setting up and using Google Analytics, including dimensions, metrics, event tracking, and cross-device attribution.

1. Introduction to Google Analytics
for web developers
Rubén Martínez

2. Google Analytics reports incoming traffic to webs
and apps
This graph compares the count of visitors from Google organic search to a website in two
periods of time.
The story it is telling us is good news: the organic traffic markedly increased in a given
month over the same period of the previous year (due to a previous investment in content
and SEO).
Introduction to Google Analytics -@RubenMartinezS

3. Google Analytics helps understand your visitors’
flows
Traffic volume by
channel e.g.
sessions per
campaign and
geolocation
Engagement
• Depth
• Density
• Duplication
Content
• A/B testing
• Path Analysis
Introduction to Google Analytics -@RubenMartinezS

4. Google Analytics is:
• A platform to track online and off-line activity of aggregated and anonymized
visitors’ data
• A behavioural reporting platform of activity of web visitors and end-users
• A bread-and-butter tool for webmasters and marketing and business analysts
• A (peculiar) dashboard interface and a well documented API
Introduction to Google Analytics -@RubenMartinezS

5. 2 Web Analytics platforms: GA and SiteCatalyst
Introduction to Google Analytics -@RubenMartinezS
Number of websites using Google
Universal Analytics (left) vs.
Omniture SiteCatalyst (below).
Graphs with the same vertical
scale and similar periods of time.
Source: builtwith.com

6. Organization of the platform
Developers can access Google Analytics via a front interface, client libraries and
APIs. This is how each components and APIs are organized:
Source: https://developers.google.com/analytics/devguides/platform/
Introduction to Google Analytics -@RubenMartinezS

7. Google Analytics is NOT:
• A transactional CRM tool
Visitors’ individual data is owned by Google Inc.
The end user has access to anonymized data only.
• A reporting tool of websites only
It can be configured to track offline and online
activity from multiple devices, including
smartphones, kiosks, consoles, etc.
• A parser of web server logs
• A KPI-centric Business Intelligence platform
Introduction to Google Analytics -@RubenMartinezS

8. Tracking code
Sign up to Google Analytics. If are tracking a website on the admin panel, setup
a property (URL). Then paste the code provided by Google (example below) on
all the pages you want to track:
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-2282690-1', 'paradigmatecnologico.com');
ga('send', 'pageview');
</script>
When the browser loads this script, it interprets the document.write and triggers
a sequence of events leading to send hits to Google’s server.
Introduction to Google Analytics -@RubenMartinezS

9. Browsers sends hits to Google Analytics server
Sequence of events:
1. The client brower requests the javascript file
2. The Google Analytics server responds with the analytics.js file
3. The client fetches, loads and executes the javascript which dynamically creates an <img>
element in the DOM
4. A GET from the browser hits the GA’s server with a URL containing appended values of the
browser and the computer. This is an image/gif request. Example:
http://www.google-analytics.
com/collect?v=1&_v=j20&a=806449001&t=pageview&_s=1&dl=http%3A%2F%2Fwww.paradigmatecnologico.com%
2F&ul=en-us&de=UTF-8&sd=24-
bit&sr=1920x1080&vp=1920x199&je=1&fl=13.0%20r0&_u=MAC~&cid=416165610.1399537988&tid=UA-2282690-
1&z=2140666386
5. The server reads the data in the image URL and stores the hit (e.g. pageview or event) for
logging and processing
Introduction to Google Analytics -@RubenMartinezS
6. The server responds with a single-pixel gif

10. The 3 most important variables: t, cid and tid
o t=pageview // Pageview hit type
o cid=416165610.1399537988 // Anonymous
Client ID
o tid=UA-2282690-1 // Tracking Web property
ID
Introduction to Google Analytics -@RubenMartinezS

11. Visualization of tags and scripts
Introduction to Google Analytics -@RubenMartinezS
The analytics.js
JavaScript library
uses a single cookie.
The cookie contains
an anonymous
identifier used to
distinguish users.

12. analytics.js Google Analytics cookies
By default, the analytics.js library sets
cookies on the top level domain, excluding
the leading dot, and sets the cookie path
to the root level (/).
The name of the cookies is _ga
Note: The analytics.js library does not
require setting cookies to transmit data to
Google Analytics.
Introduction to Google Analytics -@RubenMartinezS

13. What you CAN do with Google Analytics
• Track activity BEFORE pushing a brand new website or mobile app public
• Report activity on private areas (protected by a login and/or disallowed to
crawling bots)
• Link to Adwords (CPC), GDN (CPM) and FDA (retargeting)
• Associate engagement data from different devices and multiple sessions (great
for attribution)
• Upload transactional data of own userIDs if anonymized (great for e-commerce)
• Integrate your Google Analytics data with other business applications, e.g. via
API
• Report activity across domains (tagging is however tedious and impractical)
Introduction to Google Analytics -@RubenMartinezS

14. What you CANNOT do with Google Analyics
• Generate leads (post-click marketing). Google Analytics does not provide IP
addresses or the name of the company visiting a website for instance – and you
should not upload this information either
• Upload personally identifiable information (see userIDs above)
• Carry out experiments across multiple domains (cross domain reporting OK but not
tests A/B)
• Report –efficiently- inventory on e-commerce websites with SKUs
Introduction to Google Analytics -@RubenMartinezS

15. Metrics and dimensions
Dimensions are attributes of
• Visitors
• Sessions
• Hits: page, event
The values of dimensions are strings.
Metrics are counts (average integer or currencies).
Values of metrics are numbers.
Each custom dimension and metrics has an associated
index.
There is a maximum of 20 custom metrics and
dimensions
Introduction to Google Analytics -@RubenMartinezS

16. Event hits
Some user actions do not generate pageviews.
- completion of individual form fields (“Send”)
- external, mailto: and pdf links
- video play or complete
- AJAX, Flash, jQuery or HTML5 interactions
You want to tag some HTML elements as events. Event tracking turns a normal
<a href=“/documents/e-book.pdf”>
into
<a href=“/documents/e-book.pdf”
onclick=”ga(‘send’,’event’,’link’,’pdf’)”>
Introduction to Google Analytics -@RubenMartinezS

17. Metrics and dimensions
For example, if your page is scripted in PHP, the actual author of the page will
probably be stored in a PHP variable like $author. In your PHP template, you can
use this author variable to pass the author value to the custom dimension
ga('send', 'pageview', { 'dimension5':
'<?=$author?>' });
Introduction to Google Analytics -@RubenMartinezS

18. Content Experiments based on a multi-armed bandit
Introduction to Google Analytics -@RubenMartinezS
approach

19. Google Analytics Universal is user-centric
Advertisers cannot track users as individuals anymore due to the proliferation of
smartphones. Cookies reside in desktop browsers. Cookies are not used by mobile apps and
browsers such as Safari on iphones.
The identification of users and their sessions takes place now at server level on Universal,
not browser/cookie level.
Cookies are still used but Google warns that their format might change without warning.
Hence developers should not directly access the cookie analytics.js sets as it could lead to
script errors and incorrect data.
Instead, developers should use the get command to retrieve the clientId value when
needed. Here's how to do this:
ga(function(tracker) { var clientId =
tracker.get('clientId'); });
Introduction to Google Analytics -@RubenMartinezS

20. clientId for cross-device attribution
You can use a custom visitor ID based on customer email or ID in your database to merge
smartphone / laptop / pc sessions into one cross-device session. You can track users who login
to your website (authenticated users) by associating their clientID to their email.
<?if ($isAuthenticatedUser):?>
ga('create', 'UA-XXXX-Y', {'clientId': '<?=md5($email)?>' });
<?else:?>
ga('create', 'UA-XXXX-Y');
<?endif;?>
All users who sign in to your website will be tracked across all devices.
GA uses cookie value + domain as a unique internal identifier. If two or more websites set up
the same client ID value based on customer email, the data won't be corrupted, because they
are using different domains (and different GA profile id).
Introduction to Google Analytics -@RubenMartinezS

21. Link your acquisitions, engagement, and
conversions
In a typical e-commerce scenario, you generate unique User_IDs through the authentication
passed to an account at sign-in. The User ID will allow you to track for instance transactions
and activity on per customer basis.
To enable this feature, add the following line to your tracking code to send User-ID data to
Google Analytics.
ga('create', 'UA-XXXX-Y', { 'userId': 'USER_ID' });
ga('send', 'pageview');
where USER_ID is a string and represents the stable and unique ID retrieved from your
system.
You can then send anonymized data based on User_IDs to Google Analytics.
Introduction to Google Analytics -@RubenMartinezS

22. Thank
you!
If you enjoyed these slides or have
suggestions to improve them, let us know!
@rubenmartinezs