Читать книгу See-Through Modelling - Dominic Robertson - Страница 78

The assignment will be carried out by following Model Review Methodology, which has been used previously on a wide variety of projects.

In outline, the methodology involves the following steps:

 familiarisation – discussions with modellers and preparation of a block diagram documentation of the Model together with documentation describing its operation

 low level review, including:

 checking that SUM/total formulae appear valid

 checking that all ranges in formulae, especially lookup functions (e.g. VLOOKUP, INDEX), appear valid

 checking formulae exceptions from a map of the spreadsheet formulae (e.g. a unique formula embedded in the middle of a row of copied formulae)

 following through all unique formulae to test for logical errors

 checking formulae for consistent use of correct units (e.g. currency, tonnes, cubic metres, etc.)

 checking that all lookup formulae seek an exact match (in Excel: the fourth parameter is set to FALSE), or if not that the range it references is sorted

 checking that references in IF formulae appear valid

 checking that all range names appear to cover the appropriate cell ranges

 checking any ROUND functions to ensure that material accuracy is not lost

 reviewing any #REF/#ERR, etc., cells to establish the cause

 checking any array formulae

 checking macro/program code

 issue a list of queries and errors

 it will be the modeller’s responsibility to correct any errors identified within the Model

 once the errors have been corrected a re-review (maximum of four) will be performed to ensure that these changes have been made satisfactorily

 after the Base Case Model has been reviewed sensitivities will be tested.

In order that the review is completed as effectively as possible access to someone who is familiar with the Model is needed at all times.