A sub-ID is a custom label you attach to a click. It travels with the visitor and comes back in the postback, so every conversion can be traced to the exact publisher, placement or creative that sent it.
A simple naming scheme
- sub1: publisher
- sub2: placement
- sub3: creative
- sub4: campaign
Pick a scheme once and use it everywhere. Consistency matters more than which labels you choose.
Read the report from the top
Start at publisher level, then drill into placement, then creative. You will often find that most results come from a small share of placements.
Act on what you find
Scale the winning placements, pause the weak ones, and test a new creative on the best placement. Small, specific changes are easy to measure.

