Following are the main advantages of mapping GA4 Page/Screen Dimensions to their corresponding BigQuery fields:

1) By mapping page titles, paths, and referrers, you can visualize users’ paths through your website or app. Identify common entry and exit points, optimize navigation flow, and pinpoint areas where users drop off.

2) You can analyze which content groups, types, and specific pages resonate best with users based on metrics like page views, time spent, and engagement.

3) You can create highly targeted user segments by combining page/screen data with user demographics or behaviour. This can be a powerful tool for tailoring your marketing or product strategies to specific user groups. 

4) You can leverage page/screen data to understand user interests and preferences.

5) You can utilize page/screen data alongside other event data to build a more comprehensive picture of user touchpoints before a conversion. 

Here’s a breakdown of GA4 Page/Screen dimensions and their corresponding BigQuery fields:

Points to consider

Content ID:

While the formula event_params.value.string_value WHERE event_params.key = ‘content_id’ attempts to retrieve a content ID, it’s important to note that GA4 doesn’t inherently provide a unique identifier for content groups.

The ‘content_id’ parameter might be populated with custom IDs you have defined, but it is not a guaranteed field in every content group event.

Page location, Page path + query string, Page path and screen class, Page title and screen class, Page title and screen name:

These fields all use the same formula structure (event_params.value.string_value with key filters).

However,

It is essential to understand that GA4 might not provide all these specific parameters within every pageview event. Their presence depends on whether the relevant data was collected during the event.

Here’s a breakdown of the potentially missing data:

1. page_location: This might not be available for all events if GA4 wasn’t able to determine the full URL.
2. page_path_plus_query_string: Similar to ‘page_location‘, this combined field might be absent if some data wasn’t collected.
3. Mobile app data (screen class names): The screen class related parameters (page_path_and_screen_class, page_title_and_screen_class, page_title_and_screen_name) won’t be populated for events originating from websites.