"greater than 50%tile"?
Just have your DS5 say the alphabet and count to 20.
I know. My husband isn't particularly clued in to what kids "should" be able to do at what age, and this is our first, so perception is skewed. He often expects behavior/academics that you might find in a 9 year old.
I understand that performance varies greatly by school, but if my husband wants to set the bar at 50th, I'm fine with that because then he'll be really impressed when DS blows it out of the water. I had feared that he would expect perfection...like, nothing less than 99th, so I'm pretty happy with this.
After a bit of researching last night, I think I've found some things that will serve fine. I've got the Saxon placement test, which I think should place him in the 3rd grade level, a kindergarten skills list that includes things like "knows how old he is" and "others can understand what he's saying", a "readiness for 1st grade" quiz and a few different reading assessments that would put him at 1st grade (at least above kinder; reading's not a strong point). I think the kindergarten skills and 1st grade readiness test is going to be a big eye opener for hubby as to where DS really stands.
I thought about using the school district curriculum, polar, but it's about 5 pages long and does include some things (like history or art) that we haven't actually covered in favor of other similar things. My husband speaks English as a second language, so being presented with this long list would be somewhat overwhelming to him.
Hubby's main interest in sending DS to school is making friends, and he has the belief that if DS were to start in 2nd or 3rd grade, he wouldn't form as close friendships. This is based on his experience in school. But I don't think it applies to schools in America as much.
We're also planning to move and one of the areas we're considering might have schools that are a better fit for DS, so I'm open to the idea (though I feel I've been spoiled by homeschooling a bit...)