I know Grinity often says, test one, test 'em all -- but I can't see far enough ahead to know why or how we would test a teenager.
I don't know if I would do IQ testing at the teenager stage - I really was thinking of younger children, but here's my brainstorm.
If a younger sibling qualifies for Davidson YSP, you may as well qulify the older one so you can go to Summits together and dodge some hard issues.
If the high school doesn't work out as planned. Many a 'suprisingly gifted kid' has withered at a 'really great school.' These kids can be frustratingly individual. I know of several instances where 2 kids in YSP when to the same private school and had totally different experiences.
If the 14 year old 'crashes and burns' later in college, it might be nice to have documentation of how things were in happier times to compare to.
and most especially:
If you pretend for a second that DD14 scored exactly what DD11 scored, and would do anything at all differently than you are currently doing, then yes:'Test one, test them all.'
Otherwise the SAT is terrific - and I would do it now, in 8th grade - there are still plenty of dates- and it will be easier to compare her to the talent search kids.
Love and More Love,
Grinity