Drawbacks
One of the biggest challenges that new teachers face when basing teaching and student learning on the portfolio model is how to evaluate student portfolios.
Because portfolios cannot be simply be judged according to a checklist (for it goes against the philosophy of exploring learning as contextual and varied and encouraging students to see writing as a process and not as a static task/chore), teachers are often at a loss for criteria on which to basis their evaluation.
In addition, because portfolios are a collection of student work and thoughts, many students think that they can just submit work whenever they want.
For suggestions on how to combat these issues, see the "Responses" section of this project; this section specifically deals with issues/responses that surround the LRO, but many of these responses relate to all portfolios.