When evaluating student work and assessing for learning teachers tend to choose two trends of appraisal: product or process.
Current research is partial to process-oriented rather than merely product-oriented evaluations for many reasons.
Process-oriented evaluations are based on observing the development of the learning processes as they occur in the student throughout the lesson. It is a step-by-step interaction where there is input and output at all times between the teacher and the student. During a process-oriented evaluation the student is allowed to make mistakes, as they constitute an important part of the entire exercise. An example of a process-oriented evaluation is the teaching of writing. Time and patience are worth the investment in this type of evaluation because the teacher can really see how much the student is actually learning.
Product-oriented evaluation seeks to assess performance through a finalized product that should meet specific requirements. The teacher may or may not choose to engage in the process that will bring about the final product, because that is not what is being considered. Rather than through interaction, the product-oriented evaluation is often accompanied by a rubric that the student evaluates himself to see if the expectations of the final product are being met. It is a summative, and not a formative type of evaluation that could work as a short-term solution, for specific projects. An example of a product-oriented evaluation is, for instance, a writing homework due the next day that must include certain things to achieve a good score.
In all, both evaluations will eventually result in a product, but only in process-based the teacher gets to actually work one on one with the student.