Link measures to indicators. When building knowledge framework utilize some measurements which are already being created in organization. Pull them into the knowledge management metrics framework. Don't capture everything. Identify what users of knowledge will find non threatening in sharing.
Knowledge management deals with a higher level human function.
It is subjective and qualitative. To say that it was quantitative would give the wrong impression. Align knowledge management with expectation of work process, meaning it must be easy. Show that it is important to the organization through visible leadership. Create a community of practice support structure and provide effective knowledge sharing tools.