Table 3.

Examples of the coding scheme.

Theme	Sub-theme	Description
Instructional homework purposes (Cooper et al., 2006)	Practice or review	Homework aims to practice, review and consolidate the material taught in class, as well to study for tests (Epstein and Van Voorhis, 2001; Cooper et al., 2006).
	Diagnose learning (student, teacher or both) (emerging sub-theme)	Homework aims to help students, teachers or both monitor learning difficulties, and therefore adjust behaviors. Students can further study some contents and teachers can review contents and/or adjust their teaching methods. Exemplar quote: “Homework helps students understand what contents they understood or not…and this also helps me. If the students tell me that they did not understand something I can clarify the contents, correct mistakes…” (P5 FG8).
	Personal development	Homework aims to promote students’ responsibility, persistence, time management, work habits, autonomy (Epstein and Van Voorhis, 2001).
	Extension	Homework aims to develop cognitive skills and requires: knowledge and skills transference to new situations such as problem solving and projects (Cooper et al., 2006; Rosário et al., 2015).
Degree of individualization (Cooper et al., 2006) or adaptivity/adaptability (Trautwein et al., 2006a)	Student/groups of students or class	Homework tailored to meet the needs of each student or groups of students or to the class as a whole (Cooper et al., 2006). Homework adjusted to students’ knowledge (the teacher assign “different homework assignments depending on how good they are”, Trautwein et al., 2006a, p. 1103).
	Adjusted to the availability of students (emerging sub-theme)	Homework is assigned considering: students’ schedule, extracurricular activities, assessment tests or exams, the need for leisure… Exemplar quote: “If I learn that students have assessment tests during the week, I choose not to assign homework or, if it is really necessary, I just assign an exercise to be solved very quickly” (P3 FG10).