Should include numerical values in the audit trail for parameters?

[vegan]

Hi
I read somewhere that for the audit trail you should NOT include question-specific details (particularly numerical values) for the parameters and results, as the model needs to be flexible for future use. But that there were 2 exceptions:
- you need to highlight any issues relating to the data (e.g. data errors)
- you need to refer to a particular number as part of a reasonableness check.
If this is true, then can you please explain why the institute's solution for April 2019 Paper 1 includes the particular numerical values under the Data section which is as follows:
"The following data can be found in the parameters worksheet:
·Test maximum score = 60

·The % score required to reach the expected standard = 50%

·The number of pupils in each school = 30

.......These parameters are assumed to be correct but should be independently verified."

Could you please clarify whether or not we ought to include numerical values for parameters and results in the audit trail, particularly when no errors have been identified in them?

 

[ntickner]

Don't know where you read that, but I don't think there's a hard & fast rule here. This certainly applies to the model - no hard coding of parameter inputs, put inputs on a separate sheet, etc. But the audit trail should be a documentation & explanation of what you've done, with the purpose being that someone else can pick up what you've done and change things (and, importantly for this point, that your boss can look over it and verify you've taken the right approach).
.
If there are only a few of these, I don't see an issue putting them down. If there are loads, then doing a blanket "all parameters provided are on the Parameters sheet,... etc" is fine, perhaps highlighting the main ones to show that you've understood which ones those are.
Of course, if you need to determine the input, or modify it in any way, or do calculations on the parameters sheet (converting annual interest rates to monthly, for example) then these should definitely be called out clearly.

The overall guidance should be that you need to communicate what you've done appropriately.

One thing to add - don't put all the provided parameters down as assumptions - you'll not get any credit for assuming things you've been told, and they just get in the way of the proper assumptions and annoy the examiners.