Sandy - no, stab stitching and big stitch quilting are not the same. Usually, hand quilters will "load" several stitches on their needle by rocking the needle back and forth as they push it through the fabric. Then they pull the needle and thread all the way through. Most "traditional" hand quilters try to make their stitches as tiny as possible, 10 to 12 stitches per inch. Big stitch quilting throws the goal of 10 to 12 stitches per inch out the window, but you can still load several stitches on the needle with that technique.
Stab stitching is when the quilter simply makes one stitch at a time, instead of rocking the needle and loading several stitches at one time. It's called "stab" because the quilter stabs the needle straight down through the fabric, and then straight back up, to make the stitch.