What Is the IB (International Baccalaureate) and How Does It Work?

The IB (International Baccalaureate) is a set of international education programmes for students roughly aged 3 to 19, rather than a single exam or one qualification. It works by combining a broad subject curriculum with structured independent work and non-academic requirements, assessed through a mix of internal school-based work and externally marked exams. It tends to suit students who want breadth across subjects, are comfortable with independent research and writing, and expect to move between countries or apply to universities internationally. Schools adopt it by becoming authorised IB World Schools; Chinese International School (CIS) in Hong Kong is one example of a bilingual school that offers the IB.

The main IB programmes by stage

The IB is organised into programmes that map onto stages of schooling, so "the IB" means different things depending on the student's age.

The Diploma Programme is what most people mean when they say a student "does the IB," because it is the qualification universities most often recognise.

How the IB Diploma is structured

The DP requires students to study six subjects, normally one from each of six subject groups, with at least three (and no more than four) taken at Higher Level and the rest at Standard Level. Alongside the six subjects, every DP student completes a core of three components:

• Theory of Knowledge (TOK) — a course about how knowledge is constructed and justified across disciplines, assessed through an essay and an exhibition or presentation.
• Extended Essay (EE) — an independent research paper of up to about 4,000 words on a topic the student chooses, supervised by a school mentor.
• Creativity, Activity, Service (CAS) — a requirement to take part in a sustained programme of creative, physical, and service activities over the two years, documented rather than graded.

The core is what distinguishes the DP from a simple collection of six subjects: it forces a research project, a critical-thinking course, and out-of-classroom engagement on top of exam subjects.

How IB assessment and grading work

IB grades combine work marked inside the school with work marked or moderated externally.

• Internal assessment is set and first marked by the school's teachers — for example, laboratory work, oral assessments, or portfolios — and samples are moderated by the IB to keep standards consistent across schools.
• External assessment is the exams and submitted work marked by IB examiners, typically taken at the end of the two-year DP.
• Subject grades run from 1 (lowest) to 7 (highest) for each of the six subjects, giving a maximum of 42 points.
• Core points add up to 3 more, awarded for the combination of TOK and the Extended Essay, giving the well-known maximum of 45 points.
• The diploma is awarded when a student meets the overall points threshold and completes the core requirements, including CAS; failing conditions around core completion or specific subject results can mean the diploma is not awarded even with a high subject total.

Because internal assessment counts toward the final grade, a student's day-to-day coursework and school marking matter, not only the final exams.

How schools deliver the IB, and where CIS fits

The IB is a framework, not a fixed syllabus taught identically everywhere. Schools must be authorised to offer each programme, and they decide how to timetable subjects, which subjects and levels to offer, how to staff and resource the core, and how the IB fits alongside their own mission and language programme.

CIS in Hong Kong describes itself as a bilingual school committed to empowering students to flourish, with a focus on excellence, service, and stewardship of the future. For a family weighing the IB, that combination matters: a school's language approach, its subject offerings, and how it runs TOK, the Extended Essay, and CAS can differ substantially between IB schools even though the diploma structure is the same.

What to check when comparing the IB with other curricula

Use the same questions across every school and curriculum you consider:

• Programme offered: Is it the PYP, MYP, DP, CP, or a combination? A school may offer only some stages.
• Subject and level availability: Which six subjects can a student actually take, and are the Higher Level options they want offered?
• Language of instruction and language learning: How does the school handle bilingual or second-language teaching, and what language options count toward the IB requirements?
• Assessment load: How much internal assessment, coursework, and exam preparation does the school build into the timetable?
• Core support: How are TOK, the Extended Essay, and CAS supervised and staffed?
• University pathways: Which destinations and systems do recent graduates apply to, and does the school's IB profile match that?
• Fit for the student: Does the student want breadth across six subjects plus a research paper, or would a curriculum with fewer, deeper specialisations suit them better?

The IB is a strong fit when a student wants a broad, internationally recognised programme with independent research built in. It is a weaker fit when a student wants to specialise early, or when the school's subject offerings and language programme do not match the student's goals — which is why the school-level questions above matter as much as the IB structure itself.