Dog Food Analysis (DFA) seems like a good source of information when looked at by the unknowing. They review many dog foods both dry and canned.

What DFA Do Not Tell You: 
1. There are no authorities mentioned on this site. No Animal Nutritionists, no one listed with Master's or with a Ph.D. In fact there's no mention of anyone's name at all on this site. The site is run by Boxer World, a forum again with no one listed as an authority. 

2. They concentrate on chicken or turkey and water content as listed in the first four ingredients. What they fail to mention is the actual protein value of the ingredient. Water does not affect protein. Chicken contains between 22-26 grams of protein per 100 grams of chicken meat. Therefor, whether chicken is first or fourth, the protein amount has not changed.

DFA web page states: "As we’ve already noted, most dry pet foods are based on grains or other plant material. But the animals we’re feeding them to are carnivores and should be eating a diet that is mainly made up of meat…"

Error: Though dogs are in the scientific Order Carnivora, dogs are not obligate carnivores. A dog is neither dependent on meat-specific protein nor a very high level of protein in order to fulfill its basic dietary requirements. A dog's digestive tract is longer than that of an actual obligate carnivore. As proof, several dog food companies produce very nutritious vegetarian formulas with protein from vegetable material.

DFA web page sates: "Grains contain protein too – but it’s far less bioavailable protein for a carnivore that lacks the digestive enzymes needed to digest plants." 

Error: Wild canines not only eat available plants to obtain essential amino acids, but also obtain nutrients from vegetable matter from the stomach and intestinal contents of their herbivorous prey, which they usually consume. Domestic dogs can survive healthily on a reasonable and carefully designed vegetarian diet, particularly if eggs and milk products are included. Some sources suggest that a dog fed on a strict vegetarian diet without L-carnitine may develop dilated cardiomyopathy. -- Small animal internal medicine, R.W. Nelson, Couto page 107.

What DFA Looks For:
DFA web page states: Meat, meat and more meat products. Cats and dogs are carnivores, and a species appropriate diet for these animals must be based on meat. They have no evolved need of carbohydrates in their diet. Grains are in pet food because they’re cheaper than meat products, and are needed to hold the kibble bits together. Not because they’re species-appropriate nutrition for a carnivorous mammal.

Error: Dogs are omnivores not true carnivores. They are classified as carnivores only by dentition (dental pattern). Like bears, canines in the wild will supplement their diets with vegetation. Also, dogs are natural scavengers and will eat a variety of fruit and vegetables freely and without prompting. This is not true of carnivores.