eVars — conversion variables

What they are

eVar1 through eVar250. Called "conversion variables."

The defining characteristic: an eVar remembers. When you set an eVar, it sticks to that visitor and continues attaching itself to subsequent hits until it expires. This is called persistence, and it is the entire point of eVars.

Hit 1: eVar10 = "retirement calculator"   → eVar10 = "retirement calculator"
Hit 2: eVar10 not set                     → eVar10 STILL = "retirement calculator"
Hit 3: form submitted (event20 fires)     → event20 is CREDITED to "retirement calculator"
Hit 4: eVar10 not set                     → eVar10 STILL = "retirement calculator"
                                             ...until it expires

That credit in hit 3 is the whole game. eVars exist so you can answer "what caused this outcome?" rather than just "what happened on this hit?"

The three settings every eVar must decide

Every eVar has three configuration choices you must make:

1. Expiration — how long does it remember?
2. Allocation — when several values compete, who gets the credit?
3. Merchandising — (advanced, see Specialist Variables)

See Expiry and Allocation for the detailed decision tree.

Why eVars exist: the attribution lens

Props answer "what is this hit?" eVars answer "what led to this outcome?" If you want to know "which search terms led to form submissions", that requires an eVar. The search term stays attached to the visitor, so when the form submits, Adobe can credit the search.

Without eVars, you can only measure hits in isolation. With eVars, you measure journeys.