Google Analytics E-Commerce Tracking – Complete Guide

This post is the third in the series of frequently asked questions about various issues in Google Analytics.  The first post in the series was How Google Analytics Uses Cookies which talks about Google Analytics cookies in great details. The second post in the series was How Cross Domain tracking works in Google Analytics which talks about cross domain tracking in great detail.

I will start from the very basic and then go into advanced topic of how exactly e-commerce tracking code interacts with Google Analytics Server and how you can resolve various e-commerce tracking issues.  Once you have gone through this post (from start to finish) there will be (hopefully) nothing left for you to understand about e-commerce tracking in Google Analytics and you would end up becoming an E-Commerce Tracking code champion

 

What insight I can get from e-commerce overview report?

 

 

The e-commerce overview report provides overview of various e-commerce activities on your website like which products sell the most, your e-commerce conversion rate, total revenue generated, total products sold etc.

 

What is e-commerce conversion rate and how it is calculated?

E-commerce conversion rate is the percentage of visits which results in e-commerce transactions.

E-commerce conversion rate = (Total E-Commerce Transactions/Total visits on a website) * 100

For e.g. the e-commerce conversion rate above was calculated as:

= (3132 transactions / 262,780 visits) * 100 = 1.19%

 

What is a transaction?

Transaction (or e-commerce transaction) is a purchase order. For example 3132 transactions means 3132 purchase orders were placed on the website.  The e-commerce overview report shows the total number of transactions carried out on the website (which is 3132) in a specified time period. Each transaction is identified through a unique ID known as transaction ID.

Note: A transaction can include several products or product items as a person can buy several products or several units of a product in one transaction.

 

 

What is Total Revenue & how it is calculated?

The revenue that you see in the ‘e-commerce overview report’ is the total revenue.

Total Revenue = Total Product Revenue + Total Tax + Total Shipping

For example, the total revenue in the ‘e-commerce overview report’ was calculated as:

Total Revenue = $454,907.96 + $0.00 + $67359.46 = $522267.42

 

Note:  Your total revenue figures depend upon how your client has set up ecommerce tracking. If your client decided to exclude tax and shipping amount within the total revenue, then your total revenue and product revenue amount should be the same. If the tax information or shipping information is not supplied while setting up e-commerce tracking then Google Analytics can’t report such information in its reports and they won’t be included in the computation of total revenue.

 

What is average value and how it is calculated?

Average value or average order value (AOV) is the average value of an e-commerce transaction.

Average Value = Total Revenue/Total Transactions

For example, the AOV above was calculated as:

AOV = $522267.42 / 3132 = $166.75

 

What is unique purchase?

It is the number of product items sold in one transaction. For example a visitor can purchase 5 copies of Adobe Photoshop in one transaction.  The ‘unique purchases’ metrics that you normally see in Google analytics reports are usually either total unique purchases of a set of products or total unique purchases of a set of product items.  By default you can’t see total unique purchase of a product item.

 

 

 If you look at the total unique purchases of the first product (which is 214) you may assume that 214 product items were sold in one transaction. But this is not the case. In order to truly find out how many product items were sold in one transaction you need to add ‘transaction’ as a ‘secondary dimension in the table above and then filter out the 1st product (using advanced filter on the reporting interface):

 

 

 From the table above we can see that 8 product items were sold in one transaction with the ID ‘40625’. 6 product items were sold in the transaction with the ID ‘24751’. (Note: Transaction ids were deliberately changed to maintain confidentiality)

 

What is quantity?

It is the total number of items sold for a product or set of products.

 

 

What is Average Quantity and how it is calculated?

It is the average number of product items sold per transaction.

 

Average Quantity = Quantity / Unique Purchases

For example:

The average quantity of 1^st product is calculated as:

Average QTY = 125/124 = 1.01

The average quantity of 2^nd product is calculated as:

Average QTY = 115/109 = 1.06

 

What is product SKU?

Stock keeping unit or SKU is an alphanumeric number or string which is used to identify a product item. Following are some of the examples of SKU

1. HCS3245H
2. DB45TH
3. R567

 

What is the difference between product and product item?

Product item is the unit of a product. For example if Nokia N90 is a product then one of the pieces of this model (which is identified through a unique ID known as SKU) is a product item.

 

What is average price?

It is the price of each product item. When reported in aggregate it is the average price of a set of product items.

 

 

What is product revenue and how it is calculated?

 It is the total revenue generated from a set of products or set of product items.

Product Revenue = No. of product items sold (i.e. quantity) * Average Price

For example the product revenue of the first product in the chart above is calculated as follows:

Product Revenue = 125 * $75.47 = $9433.75

 

 

Where I can track e-commerce metrics in Google Analytics?

You can track e-commerce metrics in various ‘E-Commerce’ reports and through the e-commerce tabs found in various reports like ‘Adwords Campaigns’ reports.

 

How I can determine the per visit value across all traffic sources?

You can determine the per visit value through ‘e-commerce’ tab in ‘All Traffic’ sources report.

 

What e-commerce data is made up of?

It is made up of transaction data and item data.

 

What is transaction Data?

Transaction Data provide details about visitor’s transactions like:

• Transaction ID (or order ID)
• Store or affiliation name
• Total revenue generated from the transaction
• Tax
• Shipping Charges
• Transaction City
• Transaction State/Region
• Transaction Country

 

What is item Data?

Item data provides details about the purchased product item like:

• Transaction ID (same as in the transaction data)
• Product SKU (or item code)
• Product Name
• Product Category/Variation
• Product Price
• Product Quantity

 

 

Can you give examples of popular shopping cart softwares?

OsCommerce, Zen-Cart, Magento all are popular shopping cart softwares

 

What e-commerce tracking code is made up of?

It is made up of three methods:

1. _addTrans()
2. _addItem()
3. _TrackTrans()

 

What is _addTrans() method?

This method is used to create visitor’s transaction and to store all the information about the transaction.

Syntax: _addTrans(orderID, storeName, total, tax, shipping, city, state, country)

Example:

 

 

Do I need to supply values for all parameters of _addTrans()?

Yes. Even if some of the parameters have empty value.

 

How I can leave the value of a parameter empty?

Just don’t add anything between the quotation marks. For example:

 

 

What is _addItem() method?

This method is used to add purchased product item to visitor’s transaction and to store all the information about each unique product item (product SKU).

Syntax: _addItem(orderID, Product-SKU, Product-Name, Product-Category, Product-Price, Quantity)

Example:

 

 

Do I need to supply values for all parameters of _addItem()?

Yes. Even if some of the parameters have empty value.

 

Which parameter of _addItem() method associates a product item with a transaction?

‘orderID’

 

Which parameters I can’t leave empty in _addItem() method?

There are 4 parameters which you can’t leave empty:

1. OrderID
2. Product SKU
3. Product Price
4. Product Quantity

 

 

What is the advantage of supplying value to ‘product name’ parameter in _additem() method?

By supplying the value you can associate revenue with a product name. If you don’t supply this value then you won’t be able to see revenue generated by the sale of a particular product item in Google Analytics Product Performance report.

 

What is _trackTrans() method?

This method is used to send all the e-commerce data to Google Analytics server. The data is sent via invisible _utm.gif file. This file is requested once for each visitor’s transaction and once for each unique item (product SKU) in the transaction. So if there are 4 unique items in a visitor’s transaction (i.e. the person has bought 4 unique product items in one transaction) then there will be 5 requests for _utm.gif file.

Syntax:  _gaq.push([‘_trackTrans’]);

Note: The _trackTrans() method should always be called after: _trackPageView(), _addTrans() and _addItem() methods.

 

 

Example of an E-Commerce Tracking Code

_gaq.push([‘_addTrans’,

‘1234’,

‘skinny jeans’,

’28.8’,

‘1.89’,

’10.00’,

‘Los Angeles’,

‘California’,

‘USA’

]);

 

_gaq.push([‘_addItem’,

‘1234’,

‘SKJ49’,

’OKE Jeans’,

‘Men Jeans’,

’76.75’,

‘1’,

]);

_gaq.push([‘_trackTrans’]);

 

 

When E-Commerce Data in E-Commerce Tracking can cause problem?

It can cause problem if you supply currency identifier (like $, £, € etc) or comma (to separate numbers) in the numeric fields of _addTrans() or _addItem() methods. For example:

 

 

What is the difference between Google Analytics Tracking code (GATC) and E-Commerce Tracking code?

GATC sends page view data to Google Analytics server (via invisible _utm.gif file). Whereas e-commerce tracking code sends the ecommerce data to Google Analytics server (via invisible _utm.gif file)

 

Where do I add the e-commerce tracking code on a web page?

You add the e-commerce tracking code immediately after the following line in the Google Analytics tracking code:

_gaq.push([‘_trackPageView’]);

 

How I can use e-commerce reporting in Google Analytics?

Step-1: Configure your shopping cart software so that it can send e-commerce data to Google Analytics server.

Step-2: Add Google analytics tracking code, E-commerce tracking code and some server side script like (PHP, ASP etc) to your shopping cart receipt page (generally the ‘thank you’ page).

Step-3: Enable e-commerce reporting in your Google Analytics Profile. More details here.

 

How E-commerce Tracking Works?

 

 

 

Step-1: A visitor completes a transaction.

Step-2: Your sever processes the transaction (verify credit card details, sends confirmation mail etc)

Step-3: Your sever creates a receipt page

Step-4: Your server inserts e-commerce data into Google Analytics’ javascript of the receipt page

Step-5: Your server sends receipt page to visitor’s browser

Step-6:  As soon as the page is loaded into the visitor’s browser, GATC calls the following methods one after the other:

1. GATC calls the _trackPageView() method to send page view data to Google Analytics server.

2. GATC calls the _addTrans() method to retrieve all the information about visitor’s transaction.

3. GATC calls the _addItem() method to retrieve all the information about each unique product item in the visitor’s transaction.

4. GATC finally calls the _trackTrans() method to send all the e-commerce data (transaction data+ item data) to the Google Analytics Server via invisible _utm.gif file.

 

 

How my web server inserts e-commerce data into Google Analytics Javascript?

To insert e-commerce data you need to add a server side script (like PHP) to your shopping cart receipt page. This script should automatically retrieve ecommerce data from your shopping cart software and populate the fields of _addTrans() and _addItem() methods with it. For example, here is what your actual ecommerce tracking code may look like if you use PHP script:

<?php

If($_SERVER[SCRIPT_NAME]==/thank-you.php”) {

?>

_gaq.push([‘_addTrans’,

‘<? = $orders[‘order_id’]?>’,

‘<? = $orders[‘store_name’]?>’,

‘<? = $orders[‘total’]?>’,

‘<? = $orders[‘tax’]?>’,

‘<? = $orders[‘shipping’]?>’,

‘<? = $orders[‘city’]?>’,

‘<? = $orders[‘region’]?>’,

‘<? = $orders[‘country’]?>’,

]);

<?php

for ($i=0;$n=sizeof($products_array);$i<$n;$i++) {

?>

_gaq.push([‘_addItem’,

‘<? = $orders[‘order_id’] ?>,

‘<? =$products_array[$i][‘sku’] ?>’,

‘<? =$products_array[$i][‘name’] ?>’,

‘<? =$products_array[$i][‘category’] ?>’,

‘<? =$products_array[$i][‘price’] ?>’,

‘<? =$products_array[$i][‘quantity’] ?>’,

]);

Note: Don’t use this e-commerce tracking code on your website. It is just an example and is not even a complete code.

 

Whenever your server processes a transaction, your server side code populates the fields of _addTrans() method with the transaction data retrieved from your shopping cart software. For each unique product item (i.e. product SKU) in your visitor’s transaction, your server side code populates the fields of _addItem() method with the item data retrieved from your shopping cart software.

 

Do I need to add any special e-commerce tracking code for secure web pages (https://)?

No if you are using ga.js tracking code.

Note: the standards GATC can automatically detect when the ‘https’ protocol is being used.

 

Can Google Analytics track data from a shopping cart on other domain or sub-domain?

Yes. For more details refer to the post How cross domain tracking works in Google Analytics.

 

Where I can get more details about the various e-commerce tracking code issues?

Check out this help article.

 

 

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