In most cases, the term refers to the alignment of learning standards and teaching—i.e., how well and to what extent a school or teacher has matched the content that students are taught with the academic expectations described in learning standards—but it also refers to coherence among all the many elements that are entailed in educating students, including assessments, standardized tests, textbooks, assignments, lessons, and instructional techniques.
An incoherent curriculum, for example, might be an academic program in which teachers have independently decided what students will learn without collaborating with other teachers, basing what they teach on consistent learning expectations or considering what students learned in previous grades and will need to know in subsequent grades. Consequently, what students learn in any given course may unnecessarily repeat lessons from previous years or overlap with what is taught in other courses, or the lessons may not be appropriate for the student’s age or grade level. In addition, the assignments and textbooks given to students may not prepare them for the assessments they will have to complete, and the tests given in a course may not evaluate whether students have met the academic expectations for a particular course or grade level.
On the other hand, a coherently organized and sequenced curriculum avoids these potential issues—at least in theory. What students learn builds on what they have learned previously, and lessons are not unnecessarily repetitious or redundant across courses, subject areas, and grade levels. Teachers generally know what is being taught by other teachers, particularly teachers in the same subject area, including the subject-area material and standards taught in both previous and subsequent grade levels. All learning materials—from textbooks and reading materials to quizzes and tests—are based on the same consistent and coherent learning expectations.
Generally speaking, there are two main forms of curriculum coherence:
Vertical coherence: When a curriculum is vertically aligned or coherent, what students learn in one lesson, course, or grade level prepares them for the next lesson, course, or grade level. Teaching is purposefully structured and logically sequenced so that students learn the knowledge and skills that will progressively prepare them for more challenging, higher-level work. For a related discussion, see learning progression.
Horizontal coherence: When a curriculum is horizontally aligned or horizontally coherent, what students are learning in one ninth-grade biology course, for example, mirrors what other students are learning in a different ninth-grade biology course. In addition, the assessments, tests, and other methods teachers use to evaluate learning achievement and progress are based on what has been taught to students and the learning standards the students are expected to meet in a particular course, subject area, or grade level.
Generally speaking, the concept of a coherent curriculum grew out of the recognition that what is taught and learned in schools may not only be misaligned but—in more extreme circumstances—random, disordered, and potentially detrimental to students. For example, in some schools, teachers might decide what gets taught in a course based on personal preference, convenience, past habits, outdated instructional materials, and other factors unrelated to what is appropriate for or in the best interests of students. In addition, curriculum and instructional expectations for teachers might be uneven or nonexistent, which could lead to educational disparities that disadvantage some students. For example, one teacher might cover a lot of material in a given course and teach it engagingly, while a colleague teaching a similar course might teach far less content and teach it comparatively poorly (disparities such as these have been well documented in educational research).
For these and other reasons, in recent decades, government agencies and education policies at both the state and federal levels have either required or encouraged greater standardization in the education of students, with the general goal of improving educational quality and students’ academic achievement. Schools and districts have also embraced more coherent approaches to designing and delivering learning experiences, either proactively or in response to changes in educational policies and state requirements. The primary rationale is that when educators work and teach in concert and use developmentally appropriate and well-defined learning expectations, students will learn more and leave school better prepared. By exerting more control over the learning process, the reasoning goes schools, districts, and government agencies will be able to improve educational quality and minimize the factors that have historically produced poor educational results—although whether specific strategies produce the desired results remains a source of ongoing debates.