Meta Ads in the post-iOS14 era: how to consolidate data and not get lost in attribution

The Meta Ads ecosystem changed radically with the arrival of iOS14.5 and Apple’s transparency policy (ATT). Until then, brands could attribute conversions up to 28 days after a click on an ad, which provided a fairly complete view of how campaigns impacted sales. But with the new privacy restrictions, this window disappeared and cookie-based tracking became much less reliable.

Suddenly, brands started seeing fewer conversions in their campaigns and attribution became confusing. The Meta pixel was no longer enough to capture all interactions, and discrepancies with external tools (like Google Analytics 4) became more evident. The solution was to consolidate the data with new integrations, especially through the Conversion API (CAPI) and the use of more advanced measurement methodologies such as incrementality experiments.

TABLE OF CONTENTS

• How attribution works in Meta Ads today

• GA4 and its attribution model

• Why Meta Ads and GA4 don’t match

• Key tools you should definitely use
• How to get the most out of attribution in Meta
• Best Practices for consolidating attribution in Meta Ads

How attribution works in Meta Ads today

Unlike Google Ads, Meta does not offer attribution models like DDA or Last Click. Instead, it uses attribution windows that determine how long after an interaction a conversion can be attributed to an ad.

The options are:

• 1 day post-view (if the user only saw the ad).
• 1 day post-click (if the user clicked and converted within 24h).
• 7 days post-click (the most commonly used window for eCommerce).
• 1 day post-click + 1 day post-view (the default setting).
  
  

The logic is simple: if there is a valid click within the selected window, the conversion is attributed to that ad. If not, the last valid impression is considered.

👉 Practical example:

1. Day 1: you see an ad on Instagram Stories but don’t click.
2. Day 2: you click on an ad in Facebook Feed but don’t buy.
3. Day 5: you see another ad on Instagram and make a purchase.

If your window is 7 days post-click, Meta will attribute the conversion to the Day 2 click, even if the purchase happens three days later.

This system allows credit to be given to interactions that occur before the purchase, but it also makes results vary drastically depending on the window you use.

Attribution tools in Meta

To better understand the impact of your campaigns, Meta provides several key tools:

1. Attribution window comparison (Ads Manager)
   It allows you to see how numbers change when you choose a different window. For example, an advertiser may find that 60% of sales happen in the first 24h after the click, but if extended to 7 days, an additional 25% of conversions appear. This information is vital to adjust investment according to each product’s purchase cycle.
   
   
2. Experiments
   
   
   • A/B Tests: compare two campaign setups, audiences or creatives to understand which generates better results.
   • Conversion Lift: measures the real incremental effect of your campaigns, i.e., how many additional sales would not have happened without Meta advertising. This is key because it goes beyond traditional attribution and demonstrates the true business impact of campaigns.
     
     

Why Meta Ads and GA4 don’t match

One of the biggest frustrations for marketing teams is that Meta Ads and GA4 data almost never match. And the explanation is simple:

👉 In other words: Meta measures with an advertising focus (which ads contributed to the conversion), while GA4 has a more multichannel view of the user journey.

Reporting times in Meta

Another source of frustration is reporting delays:

• Ad spend appears almost in real time (with a small delay of minutes).
• Conversions and events take between 24 and 48 hours to be reflected.
• In the case of iOS, conversions measured with Aggregated Event Measurement can take up to 72 hours.
• Final reports may take up to 3 days to fully align.
  
  

This means that if you check your campaigns “the next day,” you probably won’t see the full picture of performance yet.

Most common mistakes when working with attribution in Meta

• Always using the default window without analyzing which one best fits the business purchase cycle.
• Not setting up CAPI properly or doing it incompletely, losing key signals.
• Comparing Meta data directly with GA4 without adjusting attribution models and windows.
• Forgetting offline data (in-store sales or call center) that completes the funnel.
  
  

Key tools you should definitely use

• Ads Manager – Attribution window comparison to understand the effect of each period.
• Experiments (A/B + Conversion Lift) to measure real incrementality.
• Offline Conversions API to integrate in-store sales.
• Adsmurai Marketing Platform (AMP) to unify Meta data with GA4, CRM and offline sales in a single dashboard and compare results without friction.
  
  

How to get the most out of attribution in Meta

1. Set up the Conversion API (CAPI) correctly: ensure event sending from server and connect CRM + offline sales.
2. Choose the right window: adjust attribution depending on your product (1 day for quick purchases, 7 days for long cycles).
3. Measure incrementality: rely on Conversion Lift to demonstrate what portion of sales are truly attributable to Meta.
4. Deduplicate events: avoid counting duplicate conversions between pixel and CAPI.
5. Use consistent UTMs to align data in GA4.
6. Centralize everything in AMP so you don’t depend on isolated reports that never match.
   
   

✅ Best Practices for consolidating attribution in Meta Ads

• CAPI as the foundation: without a properly configured Conversion API, you’ll lose key data.
• Windows adjusted to the purchase cycle: don’t always use the default, analyze how performance changes with 1 vs. 7 days.
• Align reporting with other platforms before comparing results.
• Measure incrementality: not all sales would have happened without Meta.
• Set up your technical configuration properly: event hierarchy, deduplication and UTMs.
  
  

Case study

A retailer implemented CAPI + Offline Conversions and discovered that many sales GA4 attributed to Google Search had actually started with clicks on Instagram Ads.

After integrating both data sources and running a Conversion Lift, they proved that an additional 15% of sales were attributable to Meta. With that information, they recalibrated investment and increased ROAS.

👉 Lesson: it’s not about “who’s right” between Meta and GA4, but about understanding the context and consolidating the information.

Conclusion: attribution with context

In Meta, attribution is not an exact science, it’s a way to make sense of the customer journey in a privacy-restricted environment.

👉 And this is where technology is key: with Adsmurai Marketing Platform (AMP) you consolidate online, offline and cross-channel data to have a global view of the real impact of your campaigns.

In a cookieless world, the difference lies in moving from seeing only fragments of the puzzle to having the complete picture.