Parent communication entails the sharing of all possible documentation that reflects student progress. This is not only a good idea that enables parents to be part of the academic success of their children, but it is also the best way for teachers to use that very data to differentiate instruction.
Portfolios are compilations of student progressive work that show how students are performing academically as they develop. It is meant to be an ongoing process where the teacher offers feedback as the work is completed, and the student is made responsible for their own learning.
Portfolios are different than report cards in that the latter are summative, that is, they are "the final" piece of data that intends to measure quantitatively how much the student has progressed, or whether the student is stagnant. Report cards in the 21st century should be designed in a way that the reflect an ongoing conversation between teachers and parents. Comment sections should be added, as well as a space for scheduling conferences. It is all part of the concept of the learning community.
Electronic gradebooks are widely available nowadays to document progress reports, and in them, the teacher is also able to respond to questions, schedule interviews, and maintain ongoing communication. Moreover, the e-gradebooks are great because they detail everything that is involved in the grading process thus preventing discrepancies in grading. E-mails are the enabling, free technology that maintains the academic interaction between teachers and parents, as well as teachers and older students.