How does data element persistence and eVar persistence behave

[manoj_katragadda]

Let us suppose
I have 3 eVars eVar1, eVar2, eVar3 defined as set to expire after visit.

I have data element "Populate evar1" whose Storage duration is Pageview. It has value "abc"
I have data element "Populate evar2" whose Storage duration is Pageview. It has value "xyz"
I have data element "Populate evar3" whose Storage duration is Pageview. It has value "123"

Scenario 1:
I have rule 1 for step1 where eVar1 is populated by value from data element "Populate evar1" and then send server call and then the clear vars is set.
I have rule 2 for step 2 that triggers after rule 1 where I set eVar2 value from data element "Populate evar2" and then send server call and then clears vars is set
I have rule 3 for step 3 that triggers after rule 2 where I set eVar3 value from data element "Populate evar3" and then send server call and then clears vars is set

Scenario 2:
I have rule 1 for step1 where eVar1 is populated by value from data element "Populate evar1" and then send server call and then the clear vars is set.
I have rule 2 for step 2 that triggers after rule 1 where I "clear vars first" and then set eVar2 value from data element "Populate evar2" and then send server call and then clears vars is set
I have rule 3 for step 3 that triggers after rule 2 where I set eVar3 value from data element "Populate evar3" and then send server call and then clears vars is set

Help me how the data looks for each scenario in Adobe Analytics dashboard.
Which eVars will be populated for Step 1,Step 2 and Step 3? Does eVar1 value persist on Step2 and Step 3.

Which persistence is superior whether it is data element storage duration or eVar expiry set in the reportsuite level

[DanIMS1 · Accepted solution]

Hi @manoj_katragadda 

In Adobe Analytics, if the dimensions are set to expire after the visit then it doesn't matter how you fire the rules in this case. The eVars are independent of each other, as long as you don't overwrite the value of the eVar with another value when you fire the second rule then the first eVar will persist in the reports until the end of the visit.

In your case eVar 1 will be set for step 1 and if eVars 2 & 3 aren't set prior to this step they will just be undefined at this point. On step 2 you will only set eVar 2 but in the reports you would be able to use eVar 1 and 2 together and eVar 1 will have the value set in step 1. Similarly in step 3, you will see the value of eVar 1 set in step 1 and the value of eVar 2 set in step 2 along with the newly set value for eVar 3. 

Step 1 
eVar 1 = Value 1
eVar 2 = undefined
eVar 3 = undefined

Step 2 
eVar 1 = Value 1
eVar 2 = Value 2
eVar 3 = undefined

Step 3 
eVar 1 = Value 1
eVar 2 = Value 2
eVar 3 = Value 3

Clearing the variables in Launch just clears it from being set in the next hit, but as the persistence of eVars are applied during the processing of the data the order you clear the variables has no effect unless you are overwriting it with a different value.

 

[Vinay_Chauhan]

Hi @manoj_katragadda 

In this case, the key factor is how eVar persistence works, not the data element storage duration. Data elements only determine how long a value is available within the tag manager, but it's the eVar expiry settings in Adobe Analytics that control how long the value is retained in reporting.

Since your eVars are all set to expire after the visit, Adobe will retain their values across hits during that session unless they’re explicitly overwritten.

So in both scenarios:

Step 1
eVar1 = "abc"
eVar2 = undefined
eVar3 = undefined

Step 2
eVar1 = "abc" (persisted from Step 1)
eVar2 = "xyz"
eVar3 = undefined

Step 3
eVar1 = "abc" (persisted)
eVar2 = "xyz" (persisted)
eVar3 = "123"

The use of clearVars() only affects what's sent in the next hit, it doesn’t erase persisted eVar values from reporting unless a new value replaces them. Also, runningclearVars() before setting a value is typically not needed unless you're ensuring no unintended data is carried forward in the payload.

To summarize:

• eVar persistence (as defined in the report suite settings) is what governs what gets attributed to hits, not the data element's internal storage.

• As long as you don’t overwrite the eVar, the value will carry across steps within the visit.

• Clearing vars resets the tag container state, but doesn’t affect what Adobe remembers for reporting unless new values are assigned.

Hope that helps!

[gautham_madala]

Scenario 1 (clearVars after setting values and sending server call):

Step 1:

eVar1 is set and sent.

clearVars is called after the server call.

eVar1 value persists for the visit.

Step 2:

eVar2 is set and sent.

eVar1 still persists from Step 1 due to visit-level expiry.

Hit contains: eVar1 + eVar2

Step 3:

eVar3 is set and sent.

eVar1 and eVar2 still persist.

Hit contains: eVar1 + eVar2 + eVar3

Scenario 2 (clearVars before setting eVar2):

Step 1:

eVar1 is set and sent.

clearVars is called after the server call.

eVar1 persists for the visit.

Step 2:

clearVars is called first.

eVar2 is set and sent.

Even though eVar1 is not manually set again, it still persists from Step 1.

Hit contains: eVar1 (persisted) + eVar2

Step 3:

eVar3 is set and sent.

eVar1 and eVar2 still persist.

Hit contains: eVar1 + eVar2 + eVar3

So functionally, the result is the same — because eVar persistence wins (not data element duration).
eVar expiry (set in report suite) is what controls persistence in Adobe Analytics reports — it is superior for tracking behavior across steps/pages.

[manoj_katragadda]

Thank you very much @DanIMS1 @Vinay_Chauhan @gautham_madala for the responses and clarifying the question.