Q: What does the status "EIC Not Assigned, Under Review" mean?

EIC stands for “Editor-in-Chief”, so “EIC not assigned” means that there is no Editor-in-Chief assigned to your manuscript. This step is important because it is the Editor-in-Chief that makes the final decision on whether your manuscript can undergo peer review. “Under review" could either mean internal review (journal decides whether or not to send the manuscript for peer review) or external review (peer review by an external reviewer). Given that the status of your manuscript changed to “under review” immediately after submission, we can assume that it is undergoing an internal review to determine if it can be sent for peer review.

The time taken for a journal to make a decision varies from publication to publication; it takes some journals 4-8 weeks to complete the peer review (assuming the manuscript is sent for review), though there are times when a journal could even take up to 6 months. Since it has been 3 weeks and since you have already written to the journal, I suggest you wait for a few more weeks before following up.

For a better view of journal status updates, you may find this handbook useful: Keep Calm And Wait: A Guide To Understanding Journal Statuses

Also, for help with writing to the journal, you may find this handbook useful: How To Communicate With The Journal? Peer Review Comments, Cover Letter And More

These handbooks are available from R Upskill, a sister brand providing learning programs for various aspects of a researcher’s work, including writing, submission, publication, and research promotion.

Hope that helps. And hope you hear from the journal soon!