It is very normal to see discrepancies between tracking methods.
A few common reasons include:
- Forgetting to add a conversion action to a campaign.
- First Party cookies vs Third Party cookies. LinkedIn Conversion tracking uses third party cookies whereas Google Analytics uses first party cookies. This means GA collects cookies on Safari and Apple Mobile Devices, and LinkedIn Conversion Tracking Actions do not.
- Conversions won't be counted in LinkedIn if a user logs out of Linkedin.com.
- Using different pages and URLs between third party reporting and LinkedIn Conversion Tracking.
- Different look-back windows. LinkedIn Conversion Tracking lookback window is 30 days.
- LinkedIn conversions aren't de-duplicated except in the case of conversions with multiple URLs listed.
- LinkedIn doesn't count viral conversions, only conversions that come from the paid ad itself.