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Complement of Credibility vs Ancilliary Statistic

J

jjjkkk

Member
Can somebody please clear this up for me. My understanding is that the complement of credibility is just (1-Z) and that the ancilliary statistic is the independent information.
However, I have noticed a few times the notes/exam solutions do not seem to stick to this, for example, Q9 (i) in April 2014 ASET states "The external information is known as the complement of credibility"
 
I am afraid that the problem here is that term complement of credibility isn't always uniquely defined. Sometimes it means (1-Z) see the Core Reading on page 3 of Unit 18 and sometimes it means the independent information (or the ancillary statistic) see the Core Reading in Section 4 of Unit 18 which starts on page 32.

This demonstrates that it is always important that you clearly define any terms you use in an exam question.
 
I suppose that complement of credibility is the same as ancillary statistic in the US.
 
I wouldn't get too bogged in this detail.

In general the term "ancillary statistic" and "complement of credibility" can be used interchangeably, to mean "1-Z". To me, it feels less natural for it to mean "the external information", but people would understand what you mean.
 
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