The type of interaction that occurred and led to a conversion (either click-through, view-through, or unattributed).
If you override the lookback window in a report or change the maximum gap between interactions, this may affect the attribution type displayed in your report. The new value will appear as a separate “Recalculated attribution type” field, so make sure to include that dimension in your report as well if you want to see the results of your changes.