An accommodation is a strategy that helps a student overcome or work around the disability. An example is allowing a student who has a disability that is having an adverse affect on the student's writing to give his answers orally is an accommodation. This student is still expected to know the same material and answer the same questions as fully as the other students, but he doesn’t have to write his answers to show that he knows the information.
An instructional intervention is an individualized strategy that is developed to help the student learn the content or skill to the same level as the typical student in the same grade and age level. Additional or modified instruction is provided to the student in small group or one-on-one settings to assure the student has equal access to the general education or modified curriculum.