Only someone like Mary Langford, who has set up, run, and inspected IB schools herself, could produce such a clear, condensed, no-frills treatise on this popular curriculum that is gaining momentum around the world with the speed of a rip tide.
The International Baccalaureate Explained
Schools offering the International Baccalaureate Diploma (IB Dip) prepare students for university entrance by following the IB programme over the final two years of high school. This involves taking six subjects (three at higher level and three at standard level).
In addition to the six academic subjects (two languages, a mathematics, a humanities, an experimental science, and a sixth subject representing the arts or an additional course from the previously mentioned five subject areas), all IB students have to follow a course in Theory of Knowledge (an epistimology course which questions the basis of knowledge), write a 4000 word research Extended Essay (on a subject of the student's own choosing) of college level standard, and take part in over 150 hours of non-academic activity covering creativity, physical action (e.g. sports), and service to the community.
Assessment is based on a combination of final examinations and course work, which are evaluated by external examiners worldwide, and (in some cases for coursework) by internal assessment. IB examinations for each subject are held on the same days for all students worldwide - in May in the Northern Hemisphere and in October in the case of most Southern Hemisphere schools.
Each subject is scored from 1-7, and up to 3 additional points may be awarded for TOK (Theory of Knowledge) essays and for the Extended Essay (see below). A minimum of 24 points is required to obtain the IB diploma while 45 points is the maximum.
You can judge the rigor of this program for yourself by knowing that the world average pass rate is approximately 82%. (Pupils may also opt to take certificates in the individual subject areas - without the full diploma - though these on their own may be insufficient for university entry.)
If the school has been an IB school for several years (and in rare cases, a decade or two), look at the school's most recent results but, more importantly, at their own cumulative pass rate (%) and average score (out of a top score of 45) over the total past years. In many cases, their cohort may not be large and averages can be affected by the performance of a few students.
The IB is more holistic than most exams and systems, and looks at the overall result. A pupil can get a decent diploma with high marks in their highers and relatively low marks in their standards courses. There is much room for misinterpretation and so the global score is the best measure.
Also, look to see whether the school restricts access to the IB Diploma programme to only the most able students, as is the case in many IB schools. (Always try to ascertain whether the school has manipulated its apparent results this way, whether with the GCSE's, AP exams, National Latin Exams, you name it.) If a school is not highly selective but nonetheless produces good IB Diploma results, it is an indication of good 'added value' education.
Universities like the IB programme. Many universities seek to recruit IB students because they offer both breadth of knowledge and depth, particularly in their higher level subjects.
The British Universities and Colleges Admissions Service (UCAS) has developed a tariff system that now gives greater currency to the IB scores over A-levels. An IB score of 38 points out of a maximum of 45 is equivalent to five A grades at A-level. A score of 30 IB points reflects three and a half A's at A level, which is enough to gain admission to most good universities in the UK (Oxbridge would require higher results).