This is one of my favourite pictorial depictions because it is so clear to see what helping accommodations can do for students.
(A picture illustrating the concepts of equality, equity and justice. Courtesy of Courtesy Advancing Equity and Inclusion: A Guide for Municipalities, by City for All Women Initiative (CAWI), Ottawa)
Giving students equal amounts of something is fair, but may not be helpful if they do not need it, or if it is not enough. Giving students the supports they need to succeed is helpful. However, the best response is to remove any barriers to the learning, making supports not as necessary for success.
What does this look like for assessment?
Some students may have trouble remembering. You can help these students by having the questions on a test build in difficulty -helping students access prior knowledge.
Some students may have trouble expressing what they know. Allowing multiple ways to answer questions supports students show you in a way they feel most capable.
You can support students by allowing extra time and space to answer questions. You can support students by giving clear instructions and by having the questions structured to build upon the knowledge. Your students should perceive your assessments to be fair and measuring the curricular outcomes outlined.