The skills and attitudes of students are equally important to planning and assessment as their knowledge.
To compare students' initial knowledge of a particular unit with the knowledge they have gained at the end, then the KWL Chart is a great tool. It gives you pre-assessment and summative assessment as well as an opportunity to summarize the whole class' range of knowledge. The KWHL Charts even give students an opportunity to plan how they will gain more knowledge.
However, during planning of our recent UOI, I became stuck. We wanted to learn more about our students' attitudes and skills than merely their knowledge. As knowledge of a skill and use of skill are two distinct things, a KWL wasn't going to cut it.
I created a CWA for skills and thought that while I was at it I may as well create an ABC for attitudes. Both of these charts allows us to learn more about students' prior skill and prior attitudes, allowing us to plan for these alongside their knowledge.