Why are Conversions in Google AdWords different from Goals in Google Analytics?

MoreVisibility - March 31, 2008

Q1 of 2008 started just the other day (or so it seems) and here we are, about to begin Q2. Many marketers and business owners hold quarterly status meetings, right after a quarter has ended, to evaluate the performance of their online initiatives. Specifically, they meet to evaluate their paid search campaigns (and, they should). Chances are that they are advertising with Google AdWords. Chances are also really good that they are using the Google AdWords Conversion Tracking Feature and have a Google Analytics account running at the same time. Which, of course, makes me very proud 🙂

And, if you’re like me, you like your data like Lieutenant Commander Data – with “android-like precision”. (Yes, I just dropped a Star Trek reference. My Co-Worker’s “Resistance is Futile” blog series has inspired me to reference Star Trek more often, so you have her to thank for it).

Unfortunately, due to several factors, data collected by ways of javascript and cookie creation cannot be 100% precise, no matter how hard we try to make it such. This is something that I am always reminded of when I receive a question from a client or a fellow co-worker that sounds somewhat like this:

“I am looking at my weekly / monthly / quarterly reports, and Google AdWords shows that I have received 74 conversions…but when I log in to Google Analytics, I see that I have 88 Goal Conversions for the exact same Conversion Point. Which one is right?”

There are many possibilities here. Before I can answer this, let me explain some things:

What is Google AdWords Conversion Tracking, and how it works:
The Google AdWords Conversion Tracking is a block of javascript code that is placed on a page of your website where you want your website’s visitors to ultimately wind up. This is normally a “Thank You” page that a visitor sees after they fill out an inquiry form, or a “Receipt” page that a visitor sees after they buy something from your Online Store. When a visitor lands on a page with Conversion Tracking, a cookie is placed on the visitor’s computer and data is sent to a Google AdWords server, registering this conversion and then assigning the credit for the conversion to the proper keyword, ad, ad group, and Campaign.

What is a Goal in Google Analytics, and how it works:
A Goal in Google Analytics is when someone visits a page that has been defined as a Conversion Goal within a Google Analytics profile. The idea behind what page(s) to select for Goals in GA is identical to choosing which pages to place AdWords Conversion Code on. However, Google Analytics only requires its regular tracking code to be present on that page in order to record a Goal Conversion. Upon entering your website, up to five cookies are set on a visitor’s computer, whether they reach your Goal Conversion page or not. GA takes the number of visits to your Goal Conversion page(s), and simply does the math throughout its reports.

So…why are AdWords and Analytics Conversion Numbers Different?
There are a few different reasons:

A. Cookie Deletion / Cookie Blocking Habits
Depending on a user’s browser settings, they may be blocking the AdWords Conversion Tracking cookie, and not blocking the Google Analytics cookies, or vice-versa.

B. Script Location on Conversion Page
Because these are two different scripts, there is a possibility that one script will “execute” before a user closes their browser or leaves the page, before the other script had a chance to execute.

C. Different Servers
The Server that processes AdWords Conversion Tracking is a different server from the one that processes Google Analytics data. So, much like reason B above, one server may have finished receiving information, but another server may have not finished receiving information before a user leaves the site or closes their browser.

D. Certain Google Partner Sites
Some of Google’s Search Partner Websites (where your ads may appear) cannot have their Conversions tracked with the AdWords Conversion Tracking script. However, if you’ve coded your URLs for Google Analytics, you will still see a Conversion for “google / cpc”.

E. Google AdWords can assign a conversion to a Campaign within a 30-day period
A user may not convert right away on their first visit to your site – they may come back some days or a couple of weeks later, and then convert. If you run a report in Google AdWords one day, and run the same exact report with the same date-range a week from when you ran it the first time, chances are you may see a different number of conversions between the two reports. Google Analytics cannot go back in time and credit a prior campaign or keyword with a conversion – it can only give credit for a Goal Conversion as it happens.

The combination and the mixture of all of those reasons makes it almost impossible for the AdWords Conversion Counter and Goals in Google Analytics to be identical figures.

Final Question: “So, which one is the right one / which one should I be looking at?”
The answer here is both of them. Keep in mind that neither Google AdWords nor Google Analytics are accounting packages or server logs – you cannot use those for official bookkeeping or record-keeping. I like to say, use the number of Conversions in Google AdWords and Goals in Google Analytics as guides, while analyzing and evaluating trends and habits, not for accounting purposes.