As a general rule having them answer a question or two is a traditional way to do formative assessment. With PBL I think having them refer to the rubric on a daily basis (which is on the board in a basic format) and reflecting and commenting on their progress in an online journal (convenient for teachers) for review might be a way to adapt. Basically a log or summary of progress, questions, problems, etc.

Sorry for the small font. The most difficult aspect of PBL is simply making it work with everything else regarding the demands of evaluation, available technology, state standards, communication between students, etc. I find that what I start with is not what I end with, in other words, it changes as it goes and upon reflection I see where I could have done something different. Rubrics are the hardest part, not because of planning but because of student creativity. Teachers have to come up with the highest order of Blooms questions that are difficult to answer but also connect personally… >>>