I have ongoing assessment of students' progress in all units I teach in my classroom. In this way I am able to assist students who are having difficulty grasping key concepts during the unit. I usually have the students keep a portfolio of work related to the unit that I can peruse to see if they are successful in their understanding. I keep this type of assessment fairly informal. I find that looking at students independent work gives a pretty accurate read on how well they are comprehending the material, and if there are any particular areas that they are struggling with. I then will have conferences or work individually with students to help them along. This type of informal assessment not only allows me to keep track of my students' progress, but it also can be very influential in how I set up my lessons and what I focus on in the follow up material.
Students would be more formally assessed in the final project and the work in the journal. Students would be assessed with rubrics both individually and as a group on the group project. The journal, while part of the informal ongoing assessment, would get much more concrete feedback. I would make sure to respond to journal entries as often as possible. I would leave room to write to students in the journals, and offer suggestions as well as encouragement.