Alot depends on the batting too. Cotton batting will shrink more than a poly batting. And were you working with prewashed fabrics? Or right off the bolt.... That factors in.
As QuiltE mentioned, the amount of quilting will "shrink" the quilt too.... well, not really shrink but it does compress it and make it smaller.
I would think if you wanted to minimize shrinking, you would start with prewashed cotton fabrics, then use poly batting with a minimum of quilting. (But I like to just let mine do what they do.)