Uneven Distribution in Marketo Random Sample Flow

[Raul88SD]

Hello,

I'm seeing some unexpected results in my Marketo Smart Campaign flow. Here's how it's set up:

• Step 1: Send Email
  • Choice 1: IF condition is "X" then Send Email 1
  • Choice 2: IF Random Sample is "50" then Send Email 2
  • Default Choice: Send Email 3

After running the campaign, the email send counts are:

• Email 1: 900 records
• Email 2: 700 records
• Email 3: 250 records

I expected Email 2 and Email 3 to have roughly the same number of sends because I used a 50% random sample split. Can anyone explain why I'm seeing this uneven distribution between Email 2 and Email 3?

[Agrawal_Kirti]

Hi @Raul88SD ,

Can you please confirm your target list count? Was it more than 1850?

If yes, can you tell me the count and how many were blocked when you sent the email?

If above is the condition, then I believe it randomly picked 50% records and then chose to send email to whoever is eligible and left the rest of the records. I have also faced this situation, but in my case, mostly records were blocked (email invalid), and all records received email 2 (default).

[SanfordWhiteman · Accepted solution]

I think you’re misunderstanding how Random Sample works. Bottom line: you shouldn’t combine Random Sample with other choice types in the same flow step.

Random Sample isn’t taking 50% of the people who didn’t match Choice 1. It’s taking 50% of the people who run through the flow step.*

So you have overlapping cohorts. The if condition of Choice 1 can include people who otherwise would be part of the 50% group. But of course if they match Choice 1, they cannot match Choice 2.

If the design is to...

1. send to a cohort matching a certain condition

2. split the remainder 50/50

... then remove the first cohort from the flow and use a different flow step. Even better is a separate campaign, as this kind of setup with a single campaign can be very hard to debug.

* actually more complex than that, but close enough for this discussion

[Raul88SD]

Thank you @Agrawal_Kirti  for trying to help!
It seems that Sandford figured out what I was doing wrong.

[Raul88SD]

Thank you @SanfordWhiteman  for the answer!

You're right! I've run some test and indeed, the Random Sample it's calculating all the records from the flow step, even if it's on Choice 2.

I thought that if the first matching choice applies to a record, then the Random Sample will act like all the other filters and will not take into consideration the records from Choice 1.

Because you've mentioned that "more complex than that", it would be very helpful if you could help me with any Marketo documentation or any other link from where I can deepen about how Random Sample works in Flow.