There are a couple of reasons that can lead to discrepancies in activity counts and attributions between Groove Analytics and Salesforce.  Some of the main reasons include the following.  

• Groove matches email activities to users by looking at the email addresses listed in the Email, Email Alias 1, and Email Alias 2 fields on their Salesforce User record.  (The Email Alias 1 and Email Alias 2 fields are added to your instance as part of the Groove Managed Package.  However, they may not be surfaced on your team’s User Page Layout yet.). If a sender uses an alias not entered in Salesforce, or the mapping is misconfigured, activities may be attributed to the wrong user in Groove Analytics (e.g., a reporting manager). Resolve this by ensuring all sending aliases are listed in the Email Alias 1 and Email Alias 2 fields for users in Salesforce.
• Only emails that were logged will show up in Salesforce.  Conversely, Groove Analytics surfaces emails that were logged and/or tracked for email opens.  Thus, emails that were tracked for email opens but were not logged will not show up in Salesforce.  Double-check that all your emails are logged if you see a larger activity count in Groove Analytics than in Salesforce.    
• For discrepancies in activity reports, note that Groove Analytics may only surface outbound emails, while Salesforce can show inbound and outbound, and filter logic/date ranges can differ. Review your reporting filters to make sure comparisons are apples-to-apples. If mismatches persist, contact Clari Support for tailored assistance.
• Some settings configurations, such as Best Match Email Logging being disabled, may lead to more than one Salesforce Task record being created per email while Groove Analytics will only ever count a single email once. These configurations provide more comprehensive activity logging in Salesforce by creating a Task for every Contact-Opportunity pair, but they also inflate the number of Tasks in Salesforce per email activity.  Check your Email Sync Options in Groove Profile Settings to see if they might be configured in a way that can naturally create discrepancies in Salesforce versus Groove activity reporting. 

If the discrepancy in activities that your team is seeing do not fall into any of the buckets above, you or your admin can create a case with our support team in the Clari Support Portal.