Last-click attribution
Last-click attribution gives 100% of conversion credit to the final touchpoint before the action. It is simple, comparable and structurally biased: demand-capture channels like brand search and retargeting harvest credit for demand that upper-funnel activity created.
In practice
Last-click's bias shapes budgets when taken literally - awareness activity gets defunded, the harvest channels look ever stronger, and total demand quietly erodes.
It remains useful as a consistent operational baseline, provided its bias is understood and supplemented by incrementality and modelling for allocation decisions.