All Analytics reports are based on combinations of dimensions and metrics. When viewing your data in a standard Analytics report, the first column you see in the table contains the values for a dimension, and the rest of the columns display the corresponding metrics.
Most often, you’ll use the Analytics reporting interface to access your data, since it’s easy to use for a majority of reporting and analysis needs. You can think of this interface as a layer on top of your data that allows you to organize, segment and filter your data with a set of analysis tools.
In addition to the reporting interface, you can use an API, or an Application Programming Interface, to extract your data directly from Analytics. Using the APIs you can programmatically add analytics data to your custom applications, like an internal dashboard. This can help you automate and customize the reporting process for your business.
Most of the time, when you request data from the reporting interface or the APIs you’ll receive your data almost immediately. But in some cases, where you request complex data, Analytics uses a process called sampling. Sampling helps Analytics retrieve your data faster so there’s not a long delay between when you request the data and when you receive it.