In lots of article and books I have seen that exposure compensation depends on the color, and of course 18% grey and blah blah. Now, my realization is it also depends on the metering mode. Let say your metering mode is Spot, so you just need to worry about 2-3 % of the image, if its evaluative or matrix then you need worry about the complete image, 100%. So in case Sport your headache is less as you are worrying about only a tiny portion of your picture and in case evaluative you should worry about the whole image's color composition. Let’s go by the golden rule, if it’s white then +2 exposure compensation and if it's black then -2 exposure compensation. I love wildlife photography so I always love to refer animals and their complexion for the exposure compensation discussion.
Let's first discuss about sport metering, my realization this is the easiest metering mode to deal with as explained above. I always focus near or exactly at animal eye depending upon the complexion i set the exposure. But in case of tiger I always increase the exposure a little and I have got dramatic color contrast. In case of zebra I usually reduce little bit, though lot of people say no exposure compensation. The reason is the white color in zebra is not really perfect white its a mixture of white and grey as these animal always in dust. For egrets increase of Exposure compensation and for eagle I decrease the exposure by 1 stop.
Again, if I am using matrix and evaluative metering then I need consider the whole image. Let say a black bird flying on the blue sky. Depending upon the size of the bird I set the exposure compensation which always varies. If the Sky or the bright part is covering most of the image then the exposure compensation should go towards positive side though my subject is black, and Vice versa. That's why I feel that evaluative metering is most difficult metering mode to deal with. Stay tuned for focusing next.