The external assessment
The IB uses a criterion based approach to assessment. This means that students work is judged against identified levels of attainment and not against the work of other students. At the grade award meeting which takes place once all the papers have been marked levels of attainment, in the form of grade boundaries are agreed. There is consideration of the difficulty of the exams and the performance of students and a committee of people are involved.
Several methods of assessment are used: Assessment criteria when the task in open ended, Markbands with a range of level descriptors used to judge students answers to some extended response questions, Analytic markschemes where a particular kind of response is required, and Marking notes are used to clarify assessment criteria.
Examiners are monitored throughout the marking process and ever effort is made to ensure consistency in marking.
Multiple choice questions are quite challenging and students need practice with the style.
Each question has a "distractor" or answer which is almost correct. Usually one or two answers are quite obviously wrong.
The data analysis questions at the beginning of this paper require good skills in the interpretation of graphs but also an ability to cope with unfamiliar material.
The short answer questions are the least complicated part of the external assessment. If a student knows the biology these questions resemble the work a student often does using text books and worksheets in lessons. The challenge is to be prepared to answer questions on any part of the IB Biology guide.
There is a choice of two extended response questions, students must answer all three sections of one question. Care is required in reading the questions, in particular the command term so that students give the right sort of answers. Often there is one part which requires a diagram.
Historically, many students find this exam easier than paper 2 because there is less syllabus coverage and students can prepare more thoroughly for the option material. There are two or three questions in section A which will test knowledge of practical experiment skills and analysis of results from any part of the core topics and the prescribed experiments. Section B resembles the short answer section of paper 2 except that it covers only material from the chosen option. Students should be trained in choosing the correct option and only answering questions from one option.
This investigation is assessed by the teacher in school and a sample of work is moderated by the IB and adjustments made to marks so that all centres are awarding marks in a similar standard. For further details see The Investigation pages.
Although the length of all the exams for HL is longer than the SL exams, the structure of all examinations and the investigation is the same as for SL.
The only exception is in Paper 2 where students will have a choice of two out of three extended response questions. The weighting of paper two is slightly less that the SL paper 2 to allow for assessment of the extra HL material in the option paper.