Traffic-source dimensions

Attribution is the process of assigning credit to the various marketing channels that contribute to driving traffic to your website or app. It helps you understand where your visitors are coming from and which marketing efforts are most effective in bringing them in.

Example: Consider someone who interacts with your brand multiple times before making a purchase:

1. Clicks a search ad
2. Visits your website organically
3. Sees a display ad on another website
4. Opens your marketing email

Each of these touchpoints play a role in driving the final important action.

In Google Analytics, traffic source dimensions are the building blocks for understanding and analyzing attribution. They provide the raw data that's used to determine where your visitors are coming from and how they interact with your website.

Traffic source dimension	Description	Examples
Source	Source identifies the specific platform, website, app, or online location that referred a user, giving you precise attribution for the user's last click or interaction.	Some examples of sources include "google" (search engine), "facebook.com" (referring site), "spring_newsletter" (email campaign), and "direct" (typed URL or bookmark).
Medium	Medium categorizes the type of traffic your website receives, such as through email marketing, organic search, paid advertising, referrals, or social media.	Some examples of mediums include "organic" (unpaid search), "cpc" (paid search), "referral," "social," "email," and "none" (direct traffic).
Campaign	Campaign represents a marketing initiative with a specific objective used to measure its effectiveness.	These are unique to you and your campaigns.
Campaign ID	Campaign ID identifies a specific campaign or promotion; use the same IDs for uploading campaign data.	These are unique to you and your campaigns.
Source platform	Source platform broadly classifies traffic sources, grouping them by the referring platform to provide a generalized view of traffic origins.	Some examples of source platforms include "Manual," "Google Ads," and "DV360."
Default channel grouping	Default channel grouping automatically segments traffic into broad channels based on traffic source data, providing a simplified overview of traffic patterns.	Some examples of default channel groups include Organic Search (from search results), Paid Social (from social media ads), Direct (by entering your URL), and Referral (from links on other websites).