Consistency
- Ensures fewer mistakes, promotes model integrity and makes it easier for developers and users alike to understand models more quickly
- Assists the model developer by building structured models efficiently and effectively:
- incorporating pre-defined formats and styles in a coherent manner
- requiring formulae to be copied uniformly across ranges
- presenting periodic data and formulae in columns consistently, thereby ensuring similar structures for similar worksheets
Transparency
- Many modellers often forget that key decision makers base their choices on printed material
- Models need to be clear, concise and cohesive
- Modellers should create assumptions, calculations and outputs that are recognisable instantly and user-friendly
- For example, the developer / reviewer should consider:
- the logical flow and dynamic linking of the model
- the number of categories required for particular calculations
- the nature of the assumptions together with their assumption entry methods at the design stage
Flexibility
- Models should have the structure to provide invaluable “what if?” scenario / sensitivity analysis
- End users must be able to change key assumptions within agreed parameters
Robustness
- Models must be materially free from error, mathematically accurate and readily auditable
- Develop / review spreadsheets under a philosophy of keeping things simple, consistent and transparent
- Hence, models should provide strong, inherent levels of structural, logical and formula sturdiness
- Ideally, well-built models should contain:
- no hidden macros
- in-built error, sensitivity and alert checks
- audited, established formulae