This article unpacks why analytics tools show different results, highlights the most common causes, and suggests ways to minimise confusion.

Why Do Data Discrepancies Occur?

Analytics platforms are designed for different purposes. Google Ads focuses on measuring ad interactions and conversion events that originate from its own ads. GA4 takes a holistic view of all website traffic, regardless of source. Meta Ads (Facebook/Instagram) measures interactions within its social ecosystem and attributes conversions based on its own rules. Because each tool uses distinct tracking methodologies, attribution models and reporting timeframes, exact matches are unrealistic.

Common Sources of Discrepancies

Below are the most frequent reasons why numbers differ between platforms:

Factor

Description

Impact on Metrics

Different Metrics (Clicks vs. Sessions)

Google Ads and Meta Ads report clicks (every ad click, even multiple clicks by the same user), while GA4 reports sessions (a group of interactions within a set time).

Ad platforms often show more clicks than GA4 shows sessions. A user clicking the same ad twice in 30 minutes counts as two clicks but just one session.

View‑Through Conversions

Meta and Google Ads can count view‑through conversions—when someone sees an ad but doesn’t click and later converts—whereas GA4 typically measures only click‑through conversions.

Ad platforms may credit more conversions because they include impression‑based conversions that GA4 cannot track.

Attribution Models & Lookback Windows

Tools use different attribution windows and models. For example, Meta’s default window is 7‑day click/1‑day view, while GA4 can use 30‑, 60‑ or 90‑day windows. Google Ads attributes conversions to the date of the ad click, whereas GA4 attributes them to the date of the conversion.

Conversions may be counted on different days or attributed to different channels, leading to mismatched totals.

Tag & Pixel Configuration

Incorrect or inconsistent tagging (e.g., auto‑tagging turned off, missing or duplicated tracking code, GCLID removed during redirects) can cause paid clicks to be recorded as organic or not recorded at all.

GA4 may under‑report sessions or conversions if the tracking tag fails to fire or if the GCLID (Google Click ID) is stripped from URLs.

Cookie & Privacy Restrictions

GA4 relies on first‑party cookies; if users block cookies or decline consent, GA4 cannot track them. Meta Ads can still associate actions because users are logged in and tracking doesn’t depend on cookies.

GA4 may undercount conversions compared with Meta Ads. Privacy features (e.g., iOS 14.5) also affect Meta’s tracking, sometimes causing under‑reporting there.

Cross‑Device & Cross‑Browser Tracking

Meta Ads can track logged‑in users across devices; GA4 cross‑device tracking relies on Google Signals and may be limited if signals aren’t enabled.

Conversions completed on a different device from the initial ad click may be captured in ad platforms but not always in GA4.

Conversion Counting Settings

Google Ads lets you choose whether to count every conversion or only one per ad interaction. Meta Ads may assign multiple conversions if a user completes several actions.

If tools count conversions differently (e.g., counting each purchase vs. one per user), totals will differ.

Time Zone Differences

If your ad accounts and analytics properties use different time zones, metrics for the same date range won’t align.

Ensure all platforms use the same time zone to avoid day‑based mismatches.

How to Reduce Discrepancies

While you can’t eliminate differences entirely, you can take steps to minimise them:

1. Link & Configure Accounts Correctly. Ensure your Google Ads and GA4 accounts are properly linked, use auto‑tagging and avoid manual tagging errors. Check that only the correct ad account is connected to your analytics property.
   
   
2. Align Attribution Windows. Decide on a consistent lookback window across platforms when comparing conversions. Be aware that ad platforms may count conversions on the day of the click, while GA4 counts them on the day they occur.
   
   
3. Understand Metric Definitions. Use both clicks (or link clicks) and sessions in your reports and explain to stakeholders why they differ. Recognize that ad platforms may count all interactions (likes, shares) as “clicks”.
   
   
4. Ensure Tag/Pixels Fire Properly. Verify that your GA4 tag and Meta Pixel load correctly on all pages. Avoid redirects that remove tracking parameters such as GCLID. Check that your consent management setup does not block necessary tags.
   
   
5. Consider Cross‑Device Tracking. Enable Google Signals in GA4 to improve cross‑device attribution. Remember that ad platforms may capture more cross‑device conversions because users are logged in.
   
   
6. Account for View‑Through Conversions. When evaluating Meta or Google Display campaigns, note that the platform may include impression‑based conversions that GA4 cannot measure. Factor this into your analysis.
   
   
7. Adjust for Privacy Changes. Stay informed about privacy regulations and browser updates (e.g., iOS 14.5). These changes can affect how each platform tracks data.
   
   

Conclusion

Data discrepancies are an inherent part of multi‑platform marketing analytics. Google Ads, GA4 and Meta Ads serve different purposes and therefore count clicks, sessions and conversions differently. Rather than striving for identical numbers across tools, aim to understand the causes of discrepancies and adjust your reporting accordingly. By aligning your tagging setup, attribution windows and metric definitions—and by educating stakeholders about these differences—you can gain clearer insights and make more informed decisions.

If you’d like further advice on analytics or need help interpreting your marketing data, feel free to reach out!

‍