Our kids all went through a period of study in second grade when they studied colonial Williamsburg.  Our son is a size 10-12.  We purchased the large size and it was slightly small.  He was not uncomfortable.  The elastic waist band and pant cuffs adjusted to fit.  The quality of the costume was okay.  The material is thick (non-see-through) polyester.  The ruffles and sleeves are not really hemmed, just stitched  Our son wore it five times in school, doing such activities as square dancing, and it held up well.  Would recommend it.