Rosa is a middle-school language arts teacher who sets aside time each week for a writing lab. The emphasis is on content and getting ideas down rather than memorizing grammatical rules, although one of Rosa concerns is the ability of her students to express themselves well through written language. Rosa provides opportunities for students to examine the finished and earlier drafts of various authors. She allows students to select and create projects within the general requirement of building a portfolio. Rosa is using which conceptual framework to help her students learn?