Delineating Types of Curriculum: Overt, Hidden, and Null

Most people, when asked what a school teaches, will point to textbooks, syllabi, and lesson plans. But is that truly all that happens in a classroom? Educational theorists have long argued that what students learn in school is far richer – and more complicated – than any printed curriculum document can capture. Curriculum scholar Elliot W. Eisner identified three distinct layers of curriculum that every school simultaneously delivers: the overt curriculum, which is formally taught; the hidden curriculum, which is informally absorbed; and the null curriculum, which is deliberately or unconsciously left out. Understanding all three is essential to grasping the full scope of what education actually does to – and for – students.

The overt curriculum: what schools officially teach 🔗

The overt curriculum – also called the explicit or written curriculum – is the most visible layer. It refers to the formally documented content that educational authorities, school boards, administrators, and teachers have collectively agreed to teach. It includes the specific subjects, learning objectives, instructional strategies, scope and sequence charts, textbooks, and assessment frameworks that govern classroom instruction.

This is the curriculum that appears in state standards documents, district curriculum guides, school timetables, and teachers’ lesson plans. When a Grade 8 science teacher walks into class to teach the water cycle, or a history teacher covers the Indian independence movement, they are implementing the overt curriculum. It is publicly known, formally reviewed, and intentionally designed to meet educational goals.

Characteristics of the overt curriculum 🔗

The overt curriculum is defined by three key features. First, it is explicit – everyone from students and parents to administrators knows what is supposed to be taught. Second, it is standardized – it follows officially approved guidelines, ensuring a degree of consistency across classrooms and schools. Third, it is accountable – it forms the basis of examinations, assessments, and academic performance reviews. Having a written curriculum ensures that teachers, students, and parents all know what is on the learning agenda, making lesson planning more deliberate and outcome-focused.

In India, the overt curriculum is shaped by bodies such as NCERT (National Council of Educational Research and Training) and respective state education boards, which design syllabi and prescribe textbooks across subjects and grade levels. Every prescribed chapter in a CBSE textbook is a product of the overt curriculum at work.

The hidden curriculum: what schools teach without saying so 🔗

The hidden curriculum is far less obvious – and in many ways, more powerful. The term was coined by sociologist Philip W. Jackson in his 1968 book Life in Classrooms, in which he argued that schools are not just places of academic learning but environments where students learn to navigate complex social systems. Jackson identified three key elements operating beneath the surface of school life: crowds (learning to function as part of a group), praise (learning which behaviors are rewarded), and power (learning to accept authority).

The hidden curriculum consists of the unspoken norms, values, attitudes, and social expectations that students absorb simply by being part of a school culture – without those lessons ever being written into a syllabus. It is what educators teach students without even realizing it, through their interactions, modeling, and school or classroom culture – encompassing unspoken values, beliefs, norms, and cultural expectations.

How the hidden curriculum operates 🔗

The hidden curriculum works through the structures and routines that are simply taken for granted in school life. The rigid scheduling of the school day teaches students the importance of punctuality and time management. Seating arrangements communicate hierarchy. The way a teacher responds to a raised hand versus an outburst reinforces norms around respect and order. Even break time carries lessons – students navigate unspoken rules about clique formation, self-expression, and conflict resolution during these free periods.

Consider a school that formally teaches the value of collaboration in its overt curriculum, but whose classroom culture is intensely competitive, where students are ranked and publicly compared by grades. Students may internalize individualism and rivalry as success strategies – not because anyone taught them that, but because the school environment modeled it. This is the hidden curriculum in action: it often contradicts the overt curriculum rather than reinforcing it.

The hidden curriculum also has implications for social inequality. Research shows that the hidden curriculum varies significantly across schools in different socioeconomic contexts. In well-resourced schools, students may be encouraged toward critical thinking, creativity, and leadership. In under-resourced settings, emphasis may fall on obedience and rote compliance – preparing students for very different social roles.

Positive and negative dimensions 🔗

The hidden curriculum is not inherently harmful. Many of its outcomes are valuable: students learn to respect others, develop patience, practice turn-taking, and build civic behavior. Character – including virtues like honesty, kindness, and empathy – is largely formed through the hidden curriculum, shaped by the behaviors modeled by educators and peers every day. The critical issue is whether teachers are aware of what they are transmitting, since unexamined hidden lessons can just as easily reinforce bias, gender stereotypes, or social inequality.

The null curriculum: what schools choose not to teach 🔗

If the overt curriculum is what is taught and the hidden curriculum is what is implicitly learned, the null curriculum is what is absent. The concept was formally introduced by educational theorist Elliot Eisner in 1979, who proposed that schools teach far more than what appears in their official curriculum documents – and that what they choose not to teach is equally significant.

Eisner defined the null curriculum as the options students are not afforded, the perspectives they may never know about, the concepts and skills that are not part of their intellectual repertoire. The null curriculum includes entire subjects omitted from a school’s offerings, specific topics excluded from a course, perspectives left out of a textbook narrative, and even ways of thinking that are never encouraged in the classroom.

Why topics get excluded 🔗

Exclusions from the curriculum rarely happen arbitrarily. Societal norms, schools’ institutional values, and teachers’ personal beliefs all lead to parts of the intended curriculum being omitted from actual instruction. The reasons are varied: a topic may conflict with dominant cultural or religious values; it may be considered politically sensitive; it may simply be deprioritized because it does not appear on standardized examinations; or teachers may lack adequate training to teach it confidently.

In many Indian schools, for example, topics such as comprehensive reproductive health, financial literacy, mental health awareness, or the histories of marginalized communities are frequently absent from classroom instruction – despite being directly relevant to students’ lives. A research study found that teachers excluded chapters on puberty, reproductive health, and evolution from Grade IX-X science classes, citing personal discomfort, religious objections, or fear of misinterpretation by students – even though curriculum developers argued that including these topics would address serious adolescent health concerns.

The message of absence 🔗

Eisner’s central argument about the null curriculum is sharp and important: ignorance is not simply a neutral void. When a topic is excluded, schools are implicitly communicating to students that the topic is unimportant, unworthy of inquiry, or simply does not exist. As educational scholar L.O. Wilson notes, we teach about wars but not peace; we teach about certain select cultures and histories but not others – and both our choices and our omissions send messages.

The null curriculum operates in two key dimensions, according to Eisner. The first is content: the subject matter, topics, or perspectives that are left out. The second is intellectual processes: the thinking skills – creativity, independent reasoning, divergent problem-solving – that are neglected when schooling overemphasizes memorization and rote recall. Eisner believed that the intellectual processes schools neglect may be precisely the thinking processes students need in order to flourish, and that many disciplines currently relegated to higher education should be introduced much earlier.

How the three curricula interact 🔗

The overt, hidden, and null curricula do not operate in isolation – they constantly interact, reinforce, and sometimes undermine each other. A school’s overt curriculum may formally stress equal opportunity, but its hidden curriculum – through differential teacher attention or tracking systems – may communicate that some students are more capable than others. Meanwhile, its null curriculum may omit the histories of disadvantaged groups entirely, further skewing students’ understanding of equity and society.

Together, these three dimensions form what curriculum theorists describe as the full educational experience – one that is far broader than any syllabus document. Students learn from what is taught, from how the school environment is organized, and from what is conspicuously missing. All three layers shape a student’s intellectual development, social attitudes, and sense of what knowledge matters.

Implications for educators and policymakers 🔗

For teachers, awareness of these three dimensions is professionally essential. Reflecting on the hidden curriculum means asking: what values am I modeling through my behavior, my expectations, my classroom routines? Reflecting on the null curriculum means asking: whose histories am I not including? Which skills am I not developing? Which perspectives am I inadvertently silencing?

For policymakers and curriculum designers, the null curriculum is a powerful tool for critique. Conducting curriculum audits to identify gaps, analyzing what standardized testing prioritizes, and engaging communities in conversations about what is missing are all strategies that can lead to more inclusive, equitable, and comprehensive educational design. Topics like environmental science, coding, and mental health education were largely absent from curricula decades ago – and it was deliberate attention to the null curriculum that helped bring them into mainstream schooling.

Ultimately, education is not a neutral act. Every decision to include or exclude a topic, every classroom norm that goes unchallenged, every value modeled or ignored – all of these shape who students become. Understanding curriculum as a three-layered phenomenon – overt, hidden, and null – equips educators to take greater responsibility not just for what they teach, but for the full learning environment they create.

What do you think? If you were to audit the curriculum in a school you know, which topics or perspectives do you think might be part of its null curriculum – and why might they have been left out? How aware are teachers in your context of the hidden lessons their classroom culture might be sending to students?

References

1. https://currispeak.wordpress.com/2018/05/03/the-three-curricula-that-all-schools-teach-eisner-2002/
2. https://counseling.education.wm.edu/blog/8-types-of-curriculum
3. https://www.suraasa.com/blog/types-of-curriculum
4. https://www.simplypsychology.org/hidden-curriculum.html
5. https://www.gcu.edu/blog/teaching-school-administration/what-hidden-curriculum-education
6. https://en.wikipedia.org/wiki/Hidden_curriculum
7. https://repetitio.ai/subjects/sociology/education/the-hidden-curriculum/
8. https://study.com/academy/lesson/types-of-curriculum-null-curriculum.html
9. https://openoregon.pressbooks.pub/foundationsofeducation/chapter/chapter-7-curriculum-and-academic-standards/
10. https://files.eric.ed.gov/fulltext/EJ1155928.pdf
11. https://www.thecollectivefuturesproject.com/blog/the-null-curriculum
12. https://thesecondprinciple.com/instructional-design/types-of-curriculum/
13. https://courses.lumenlearning.com/suny-hvcc-education106/chapter/4-2-sociological-influences-of-the-four-curricula/
14. https://www.numberanalytics.com/blog/ultimate-guide-null-curriculum