Good grief. I knew something was fishy when I bought the little set of metal measuring spoons. The sizes just didn't seem right. But I wasn't going to use them for cooking - just dosing out vitamin supplement to add to my chickens' water - so I didn't obsess over it.
Well. Then one day I had a minute and I put the set side by side with my regular, trusted kitchen measuring spoons. Ha. I don't know how they managed this, but the teaspoon and the half teaspoon are THE SAME SIZE (ok, not exactly - one measures out 6 grams, the other one 5 grams). The 1/4 teaspoon is about the same size as a proper half teaspoon. The tablespoon looked sort of ok, but I didn't check.
Anyway - it's a word to the wise. Don't trust measuring thingies from the dollar store. If I'd been baking something finicky, it would have been a real problem.