IMPORTANT: Although Attribution Metrics display Profit, Sales, ROAS, and Conversions - these metrics differ from those listed under your Financial and Ad Metrics. See below.
Attribution Metrics include all sales associated with your Channel campaigns based on data sourced directly from Google Analytics. Attribution metrics can be incredibly useful in helping you to discover how shoppers interact with your website when conversions do not necessarily occur directly from clicks on your ads.
Due to this, Attribution Data can differ greatly in comparison to your Financial Metrics and Ad Metrics.
There are two types of Attribution Interaction:
First Interaction: The value of a metric for which your campaigns were the first interaction in a 30-day look-back window. For example when someone clicks one of your ads, then goes to your site directly, leaves, but returns and then buys the product through organic search.
Last Interaction: The value of a metric for which your campaigns were the last or only interaction in a 30-day look-back window. For example when someone finds your organically, visits again via a direct link, and then ends with purchasing from one of your ad campaigns.
Here is a diagram that shows some of the correlation between different attribution sources.