Deborah Ruf's LOG and checklist are a load of pig's intestines IMO. It's hard, but really you just have to wait it out to see what sort of brain and child you have on your hands. No simple checklist is going to replace maturity, observation of the child and real testing once they're old enough.
I think this is really good advice. And, I agree about the LOGs.
I don't think attention span in preschoolers is linked to intelligence. My child's temperament is so reasonable, calm, and easy going. Her attention span has always been limitless. That is not the temperament I think of when I think of gifted children. I do think it helps. I actually think it is this temperament, and not intelligence, that makes her look so advanced at a young age. Most toddlers do not sit still and let you read anything to them all day thereby learning heaps of information. (In this case it really comes down to the caregiver's attention span, right?) Most four-year-olds are not able to sit and read books to themselves in 2 and 3 hour stretches daily.
I think it is a great advantage, but long attention span has only made me doubt more. I will say that it was clearly evident to many that have met her that DD's attention span was off the charts loooooong. I never had any doubt in that.
