Subtitle: Unlocking Accurate Ad Performance Measurement Amid Privacy Changes

Facebook's attribution system is essential to measuring ad performance, but in 2025, signal loss and privacy changes have made the process more fragile than ever. One feature that could change how we evaluate performance is Meta's new incremental attribution model.

Here’s what marketers need to understand now:

What Is Facebook Attribution?

Facebook attribution is how Meta determines which ad deserves credit for a conversion. It connects the dots between a user clicking or viewing an ad and taking action (such as purchasing) within a specified timeframe, known as the attribution window.

Attribution Windows: What Meta Supports in 2025

Meta currently supports a few fixed attribution windows:

• 1-day click
• 7-day click
• 7-day click + 1-day view (default)

Meta won't count that conversion if someone converts outside that window, on day 8 after clicking your ad. This can result in misleading ROAS, especially for products with longer decision cycles.

Introducing: Incremental Attribution (New in 2025)

Incremental attribution is Meta's new model, introduced to sit between shorter and longer windows. It estimates which conversions are caused by your ads, even if they don’t fall neatly within a traditional attribution window.

• It doesn't change the length of the window.
• It uses modeled data to estimate lift in conversions from ad exposure.
• Think of it as a midpoint: between 1-day and 7-day click. More realistic than a 1-day click, but more conservative than 7-day click.

Attribution Depends on ClickID

To understand how attribution works, you have to understand ClickID.

Every visitor who clicks an ad carries a unique identifier:

• Meta uses fbc
• Google uses gclid

This ID ties all behavioral events (add to cart, checkout, purchase) back to that specific click. If your ClickID is dropped due to:

• Domain jumping
• Poor cookie handling
• Browser-side-only tracking

Then Meta can’t link your conversions back to the ad and attribution breaks.

Tracking vs. Attribution: Where Things Break

Attribution requires two things:

1. Behavioral event data (PageView, AddToCart, Purchase)
2. Attribution metadata (ClickID, External ID, etc.)

Browser-only pixels often lose ClickID due to:

• ITP/browser restrictions
• Incomplete data across domains

This leads to conversion loss in Ads Manager, even if Events Manager shows the events were tracked.

Fix It With Server-Side + Webhook Tracking

Aimerce fixes this issue using:

• Webhook + webpixel: ensures that ClickID is passed and captured across all steps
• Server-side pixel: bypasses browser restrictions and guarantees clean, deduplicated data
• Automatic Advanced Matching: sends full identifier stack (email, phone, fbp/fbc) to Meta, increasing EMQ scores

Why This Matters

When ClickID and attribution data are intact:

• Meta can accurately assign conversions
• You scale based on truth, not guesswork
• Incremental attribution becomes reliable, not noise

When ClickID is missing:

• Meta underreports conversions
• ROAS is misleading
• Winning campaigns may look like losers

If you’re evaluating performance with broken attribution, you’re flying blind.

TL;DR:

• Meta attribution relies on ClickID (fbc)
• Attribution windows haven’t changed, but Meta now offers incremental modeling
• Incremental attribution is only useful if your tracking is clean
• Aimerce restores visibility by fixing the ClickID chain end-to-end