I recently researched expert opinion letters for an employment-based immigration case and discovered that they can play an important role when demonstrating specialized knowledge, degree equivalency, or professional qualifications.
An Expert Opinion Letter is typically prepared by a qualified professor, industry expert, or credential evaluator who reviews an individual's education and work experience and provides an independent professional assessment. These letters are commonly used for H-1B, EB-2 NIW, EB-1, O-1, TN, and L-1 visa petitions.
One provider I found was AAE Evaluations. They offer expert opinion letters prepared by experienced evaluators and subject matter experts. Their services can help establish:
Degree equivalency based on education and work experience
Specialized occupation requirements for H-1B petitions
They also provide education evaluations, work experience evaluations, and other immigration support services: https://aaeevaluations.com/services/
If you're working with an immigration attorney or preparing a petition, it may be worth discussing whether an expert opinion letter could strengthen your case.