props vs. evar discrepancy

[Herder]

Hello Analytics Experts,

I have a clarification between prop and eVar reporting differences.

Here is the Scenario:
1. We're using prop1 and eVar5 to hold the same data, and pass in the reporting.
2. The prop1 and eVar5 will only show in the beacons after a successful conversion which is happening after a form completion.

3. After the form completion, the data that holds the value for prop1 and eVar5 will be cleared via clear beacons, and confirm this, even if you click somewhere on the page, the prop1 and eVar5 will not show up.

Questions:
1. Considering that the prop1 and eVar5 hold the same data, why is it that the eVar has a higher count than that prop?

2. Why is it that the eVar has unspecified values, while the prop is none?

Thank you in advance

[Rajeshwari · Accepted solution]

with regards to #1. Prop expire or do not hold value beyond image request. eVar persist the value as per the backend setting of Adobe Analytics admin console. However, by default eVar persistence till visits and due to this nature of eVar, it has higher count as prop even if sending same values in both variable.

regarding #2. if you are looking the eVar with metrics like visit, Unique visitors or any other custom metrics which is not associated or pass with eVar in same inage request then in those scenarios you will get the 'unspecified' value. if you will user the 'evar instance' metrics then you will not see the 'unspecified' line item.

Hope this will help.

[Jennifer_Dungan]

Yes, attribution on your eVars is the issue...

ClearVars is used to clear values that are set on the page (i.e. reset the variable value in the JS - mostly for potential reuse on clicks, or on SPAs where you don't want a lingering value to be sent in your tracking)... but eVars work as follows (lets use a campaign that is set on entering the site):

• Page 1 (Campaign X)
  • prop1 = "x"
  • eVar1 = "x"
  • eVar1 Instance (metric) is also set
• Page 2
  • prop1 - not set (there is no attribution on a prop)
  • eVar1 = "x" (as the eVar is set to a visit level attribution)
  • eVar1 Instance (metric) is not set, because no explicit value is set to the eVar
• Page 3
  • prop1 - not set (there is no attribution on a prop)
  • eVar1 = "x" (as the eVar is set to a visit level attribution)
  • eVar1 Instance (metric) is not set, because no explicit value is set to the eVar
• End of Visit
• Page 4 (next visit - no campaign)
  • no prop1 OR eVar1

if you want your eVar to act like the prop, you must change the eVar expiry from "Visit" (default setting) to "Hit"

To borrow a phase from a friend:

eVars are like chewing gum on a sidewalk... once you step in it, it sticks to your shoe and follows you around until you dislodge it

Props are like a banana peel, you step in it with an immediate action, then continue on your way forgetting about it.

[RobertBlakeley]

This comes down to which metrics you are using. To directly compare the prop and evar, you would use PV for the prop and evar5 Instances for the evar. (As Jennifer's example outlines.)

Also, in my experience, sometimes when setting two values separately for the same thing, one or the other does not fire all the time as expected. This could be due to a race condition or some other code issue. You could use processing rules to copy one of the values into the other which would force them in sync. But that depends on some details of the purpose of using two variables.