Analyze Experiment Data in Google Analytics

Dalton sends a dalton event to Google Analytics on every qualifying page visit. The event carries a type parameter that identifies which group the visitor is in:

• dalton: Dalton-optimized traffic seeing your experiments (80% by default)
• holdout: Holdout traffic seeing your original, unmodified pages (20% by default)

The percentage of traffic flowing to the holdout group can be changed in the settings.

Verify Events Are Being Received

Before creating audiences, confirm GA4 is actually receiving Dalton events.

1. Open the Realtime overview report in GA4.
2. Look for the dalton event in the event count card.
3. Click the dalton event — you should see the type parameter with values dalton and holdout.

If you don't see the dalton event or the type parameter, your audiences will stay empty. See the FAQ below for troubleshooting.

Register type as a Custom Dimension

Before you can break reports down by group or build audiences reliably, register the dalton event's type parameter as a custom dimension. This is what makes type selectable in reports, explorations, and audience conditions.

1. In GA4, go to Admin → Custom definitions → Custom dimensions.
2. Click Create custom dimension.
3. Fill in:
   • Dimension name: e.g. Dalton Type (this is the label you'll see in reports)
   • Scope: Event
   • Event parameter: type
4. Click Save.

Give it a few hours

Custom dimensions only apply to data collected after they're created — they don't backfill. Expect a delay (often up to 24–48 hours) before Dalton Type is populated in your reports.

Setup Dalton Audiences

Create two audiences in GA4 to compare experiment results.

Step 1: Create New Audience

Navigate to Settings → Audiences → New Audience

Step 2: Configure Custom Audience

1. Click Create a custom audience
2. Select Events as source
3. Choose dalton event

Step 3: Set Audience Conditions

Create two audiences using the type parameter, and name them so they're easy to recognize in reports:

• Optimized — where type = dalton
• Holdout — where type = holdout

Using Dalton Audiences

Apply your audiences to any GA4 report to compare performance.

Add Comparison

In any report (e.g., Landing Pages), click Add Comparison at the top.

Create comparison groups based on Audience Name.

Other Ways to Compare Dalton vs. Holdout

Audiences aren't the only option. Both approaches below rely on session segments that you build once and reuse.

First, create two session segments in an exploration, each based on the condition session contains the dalton event where type = ...:

• Optimized — session contains the dalton event where type = dalton
• Holdout — session contains the dalton event where type = holdout

Then apply them in either report:

• Funnel exploration: In Explore → Funnel exploration, build your conversion funnel (e.g. landing → add to cart → purchase) and apply the two session segments. This shows step-by-step completion and drop-off side by side for the Optimized and Holdout groups, so you can see exactly where Dalton's variants help.
• Any exploration: Apply the same segments to a free-form or other exploration to compare any metric — conversion rate, revenue, engagement — between the two groups at the session level.

FAQ

What if my audiences stay empty?

Empty audiences almost always mean GA4 isn't receiving dalton events. Check the Realtime overview report — if no dalton event appears there, the audience has nothing to populate from.

Common causes:

• The Dalton script isn't installed on the pages you're testing, or hasn't loaded yet.
• Your GA4 Measurement ID isn't configured in Dalton settings.
• A consent banner is blocking analytics before the user accepts.
• Ad blockers are blocking GA4 in your own testing session — try an incognito window without extensions.

Why don't I see the type parameter when clicking the event?

If the dalton event shows up but the type parameter is missing, the event is firing but parameters aren't being passed through. Make sure your GA4 property is up to date and that no custom GTM configuration is stripping event parameters.

How long until audiences populate?

New GA4 audiences only include users who match after the audience was created — they don't backfill. Expect a few hours before meaningful numbers appear, and up to 24–48 hours for the audience to be usable in comparisons.

Can I use type as a dimension instead of creating audiences?

Yes. Once you've registered type as a custom dimension (see Register type as a Custom Dimension), you can break down any report by it directly, or use it in a funnel exploration or session segment — without creating audiences. Audiences are still useful for comparisons across multiple reports.