IB Chemistry Web

External Moderation of Internal Assessment

What is moderation?

This is the process whereby the grades given to a student's Internal Assessment work (i.e. the practical course) are checked by an external moderator. This external moderator may be anywhere in the world - he/she is appointed by the IBO to do the job. He/she "moderates" the grades given by a teacher to his/her students. Which basically means that the marks are checked by the moderator who then either agrees with the marks given by the teacher or who "moderates" or corrects the marks, raising or lowering them appropriately.

So the good news for students is that THEY are not being marked by the moderators, it is the teacher's marking that is being checked.

The bad news is that if the teacher has his/her assessments incorrectly graded in the first place then any changes made by the moderator will be reflected in ALL the grades of that teacher's students.

This is best explained by an example:

  • Let's assume Professor Plum sets his students a practical which he then grades for Planning A and his student, Nigel Molesworth is given a 3.
  • When moderation time comes along the IBO tells Professor Plum to submit a series of samples including those of Nigel Molesworth.
  • These samples are sent to a moderator somewhere in the world who decides that Professor Plum has been extremely generous with his grading of Planning A in Nigel's book and that it should have been given a grade of 1 instead of 3.
  • This moderator will then consider that ALL of the marking done on Planning A by Professor Plum has been generous and he will downgrade the marks of ALL of Professor Plum's students by two points.
  • The consequences could be disasterous for Millie Swot (another student) who is on the borderline between 6 and 7 overall. Her practicals (which may be completely correctly assessed) will be downgraded as well and she will not achieve the grade that she deserves.

What do we get from this?

Two messages come through clearly from the IBO.

  1. The practicals set by the teacher MUST be appropriate to assess the criteria for Internal Assessment
  2. The assessment done by the teacher MUST be correct according to the descriptors given for each criterion

Where are the pitfalls?

The biggest problem for the teacher is to make the Internal Assessment task appropriate for the criterion under assessment. This is particularly true for planning A and B. The task given must not be proscriptive for the students.

This means that opportunity to produce a research question must be placed in the hands of the students and not given to the students.


An example of bad practice

The following is an example of what NOT to give for a planning task:

"Investigate the enthalpy of neutralisation in the reaction between sulphuric acid and sodium hydroxide"

This tells the students what to look for and leaves no room for developing individual ideas. The choice of METHOD could be argued for planning B assessment but as the student is given the research question it cannot be used for planning A. A teacher submitting this as an sample for planning A moderation will get hammered (i.e. the grades of his/her students will be lowered overall)

An example of good practice:

"Investigate an electrochemical cell"

In this case the student is given free range to select variables and investigate their effect on the EMF of an electrochemical cell.

Possible variables:

  • Temperature
  • Concentration of solutions
  • Depth of electrodes
  • Type of electrodes
  • Nature of solutions
  • Nature of electrodes
  • Nature of salt bridge
  • etc.

It is now up to the student to formulate the research question and a hypothesis.

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