Attribution in Google analytics is the process of identifying a set of user events across screens and touchpoints that contribute in some manner to the desired outcome and then assigning value to each of these events.
Last Interaction Attribution- The last interaction attribution is shown in the details about the last clicks on the website.
First Interaction Attribution- In the first interaction attribution, work like where to get the first interaction to get the complete credit. Means if anyone visits your site to facebook first time and visits next time directly with the help of URL, the credit will go to facebook where the fist time site is visited.
Last Non-Direct Click- The last click that is not direct traffic receives all credit for the conversion.
Linear Attribution- Each interaction leading up to the conversion receives an equal amount of credit for the conversion.
Time Decay Attribution- The closer the interaction is to the time of the conversion, the more value that interaction is assigned.
Position-Based Attribution- 40% of the credit is given to the first & last interaction, with the remaining 20% spread out between any interaction in the middle.
Custom Attribution Models- Each interaction leading up to conversion is assigned a custom % amount of the conversion value.