I am guessing that if the person who tested your child is familiar with your school district he knows what tests are generally accepted - each of the private providers we've worked with has been familiar with what will and won't work in our school district. You can most likely verify what he told you re test & score by looking for gifted program admission info on your school district website or by asking the gifted department in your school district.
I do think you'll see a lot of posts online suggesting the Wechsler is a more reliable or more widely-used ability test - but that doesn't mean it's the test your school district uses. It's been our experience that school districts choose screening tests for gifted programs based on length (shorter than typical private testing) and (most likely - this is a guess here!) - cost. The shorter screeners and group tests take less time on the part of school staff, and I'm guessing also cost less to purchase and train personnel to use. Please note, I don't know anything about the RIAS so I could be way off in my guesstimating
Best wishes,
polarbear
