http://www.dogfoodanalysis.com/dog_food_reviews/

Here try that link, it will explain things better than I can. There is an indepth reveiw of ingredient lists, pros and cons, and the whys of lots of different foods, including wellness and foster's and smith, and the star factor is basically based on ingredient lists. It's not perfect but makes it much easier to compare foods. Wellness and F&S are good foods, but there are several that are as good and some that are better, although every dog is different and what works best for one may not work the same for another, even in high quality foods, just like people, but based on "healthiness" of the food, if that's what you are comparing, with ingredients etc, this will give good comparisons. In fact the Wellness is rated a better food than the Foster's and Smith's.