I think it depends on the yarn and needle sizes. 3/4 or 4/5 is usually the ratio that I find works. Sometimes a pattern will tell you how many stitches to pick up, and you can divide the edge into sections so you pick up the same number of stitches in each, but that doesn't help if you make the sweater longer or shorter than called for.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry