Assigning additional reviewers? I have submitted a paper that I have written at a well-known journal and the current status is: Assigning additional reviewers. I have just submitted my paper last week. I am wondering why this is the case because from what I know, initially the associate editor assigns 2-3 reviewers and when they complete their reviews, if the editor feel that the reviews were not sufficient may assign additional reviewers. So why is my paper being assigned additional reviewers at the beginning of the review process? Thanks.
Speaking as an editor, two possibilities seem likely:


The journal website reports "additional reviewers" when more reviewers are assigned, even if the reviews are not returned yet.  Thus, it might be that 2 reviewers accepted invitations, 1 declined, and another invitation or two are outstanding, and this would still be reported as "assigning additional reviewers" because they system's not very subtle.
Some reviewers returned either very fast and contradictory or very fast and worthless reviews, and the editor is getting more to help resolve the decision.


Either way, don't fret about it: your paper is being handled, and there's nothing that you can or should do right now.