Hello! Could you please help me to better understand how the

Extra UserId property

(Mixpanel data source integration) works. I have two questions. Let me ask them with examples: 1. Example 1 ▪︎ A user opens website first time and Mixpanel assigns

distinct_id

‘abc123’. ▪︎ Then this user makes a purchase and and we call mixpanel.identify() with our internal

user_id

‘789’. ▪︎ Also we save

user_id

‘789’ as a super property in Mixpanel ◦ Question 1 How many users are identified with GrowthBook

Extra UserId Property

=

user_id

? ◦ Question 2 How many users are identified without

Extra UserId Property

set in GrowthBook? 2. Example 2: ▪︎ A user opens website first time and Mixpanel assigns

distinct_id

‘abc123’. We also assign

GB_id

= ‘zyz987’ and save it as a Mixpanel super-property ▪︎ After a certain moment Mixpanel

distinct_id

changes, but

GB_id

remains the same ◦ Question 1 How many users are identified with GrowthBook

Extra UserId Property

=

GB_id

? ◦ Question 2 How many users are identified without

Extra UserId Property

set in GrowthBook? Thank you in advance!

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Would someone be kind enough to assist with this matter, please?

Hey, Dmitry - absolutely. I'm not super familiar with the Mixpanel integration - let me sync with the team to get an answer for you on this.

Thank you Michael! It’s interesting… Are there any suggestions on how to set up Growthbook experiments for unregistered customers with the KPIs that happen after registration. For example, CR First page visit -> Purchase (after registration). It means that at the moment of registration Mixpanel distinct id changes and GrowthBook library set up a new version to a user (if we pass Mixpanel distinct id to GrowthBook).

@swift-belgium-56757 To confirm, in your setup, the

distinctId

changes whenever a user registers? In that case, even if you were to create your own ID that persisted before and after registration and set it to the

extraUserId

property, it would result in two users, since we'd add the additional

GROUPBY

clause. If the

distinctId

is changing after registration, we don't support that use case with our Mixpanel data source. We recommend switching to a SQL data warehouse instead for more flexibility for how to handle different IDs.

To confirm, in your setup, the

distinctId

changes whenever a user registers?

Yes - a new distinct id is assigned after registration / login

In that case, even if you were to create your own ID that persisted before and after registration and set it to the

extraUserId

property, it would result in two users, since we’d add the additional

GROUPBY

clause.

If the

distinctId

is changing after registration, we don’t support that use case with our Mixpanel data source. We recommend switching to a SQL data warehouse instead for more flexibility for how to handle different IDs.

Thanks for the recommendation. Giving Mixpanel one last chance, do you think this setup will work correctly? • Our ID (the same for a user - before and after registration) will be used only for GrowthBook, which means that Mixpanel unique ID will not be used for traffic distribution. • No

extraUserId

in the GB / Mixpanel integration. •

Experiment started

Mixpanel event will be sent based on what version is assigned by GrowthBook. • Mixpanel will only be used for reporting with it’s own identity management mechanism.

@swift-belgium-56757 I'm not 100% sure. When you're tracking experiment assignments, are you calling:

mixpanel.track("$experiment_started", {
      "Experiment name": experiment.key,
      "Variant name": result.variationId,
      $source: "growthbook",
    });

I'm not sure familiar with Mixpanel's track method - is there a way to override the

distinct_id

? From what I can tell, that

distinct_id

is automatically included in the

mixpanel.track

call. If you were to pass in your ID when instantiating Growthbook (e.g.)

// Add the mixpanel user id to the GrowthBook attributes when it loads:
mixpanel.init("[YOUR PROJECT TOKEN]", {
  debug: true,
  loaded: function (mx) {
    growthbook.setAttributes({
      ...growthbook.getAttributes(),
      id: <YOUR ID>, //instead of mx.get_distinct_id(),
    });
  },
});

Then when it came time to analyze the experiment, the

ids

wouldn't match up, unless you were able to override the

distinct_id

when calling

mixpanel.track()

.

Thank you @billions-xylophone-11752!