Contracts - "A learning contract is an agreement between a student and a teacher (and sometimes parents, too). Contracts establish the parameters for responsible, independent work. Contracts may respond to interest, learning profile, and readiness differentiation. One benefit of using contracts is the opportunity they offer students to practice the skills of time management, taking responsibility for their own learning, and self-assessment." (Tomlinson & Strickland, p. 354).
C. Tomlinson & C. Strickland (2005) Differentiation in Practice: A Resource Guide for Differentiating Curriculum Grades 9-12. ASCD.