Rewarding effort, in and of itself, also, and paradoxically, devalues it.
I teach an AP English course. Every year I have a handful who have never been in an honors English course, and one or two who are coming straight out of “sheltered” classes for our English-as-a-second-language learners (though that is often a poor discription, since many of our “ESL” students already have several African or middle Eastern languages. I have a student this year who speaks Urdu, Farsi, and Hindi. Isn’t that cool?) Anyway, when these kids come to me, terrified after the first couple days of school, I tell them flat out that they are behind. That the course is going to be harder for then than for anyone else. And that I won’t take this into consideration when I grade their work. However, I also tell them that they will pass–barely–if they try on every assignment and do a good job on every chance for an “easy” grade (which is true–the class is balenced that way.). And I tell them that they will catch up, but it will take them most of the first semester, and that when they seem to be getting better, that they can be confidant that they are.
Kids really respond well to this speech. They want to improve, and they want to know that when their grades rise, it isn’t because their teacher feels sorry for them. I do make sure that they know I notice their effort–I do a lot of cheerleading and handholding–but I fight–and I think usually succed–to resist the temptation to have a different grading scale for the kids I know are trying.
At the same time, you could argue that my class has an element of “effort” grading because there are easy grades, and they are enough to almost pass–so it takes only a little success on the hard stuff to at least get a low C. However, my easy assignments are not fluff–they all serve a purpose in my master plan, and they all teach something–if all you do are the easy assignments, you will learn quite a bit. So, no, I don’t think that effort ought to be heavily weighted in the classroom, especially not in college or in a college level course.