Hi Zach. Instead of a report, I would recommend a proactive notification. We have a great app that I highly recommend for companies using time tracking called "Time Reporting Compliance" - https://www.clarizen.com/apps/time-reporting-compliance/
This will let you set a target number of hours for each user and they will receive notifications listing these hours versus the number reported so far when entering in time. You can also use a custom action at any time to send an email notification to all users that have submitted less time than their target. The best part is that you can modify the rules to suit your business use case.