In My assessments, under the Reviewers header you can see how many reviewers you have added, and how many more reviewers are needed to give you a healthy report.
You can see a snapshot of your reviewers' progress by hovering over the number of completed reviews, which will open up a pop-up box as below:
Clicking on the number of completed reviews will allow you to manage your reviewers and see the following information:
Survey Completed - whether they have completed their review of your survey.
User Status - whether the reviewer has registered to the platform.
Registration Expiry - the date that the registration invitation to the platform will expire for the selected reviewer.