Most people think skill differentiates a 'spreadsheeter' from a professional modeler. That's not how I see it. Non-professionals can be highly skilled. I know some. In my opinion what differentiates a 'spreadsheeter' from a 'professional modeler' is in who uses the model: the modeler... or someone else.

There are fundamental differences in how we model when we model for ourselves versus others. When modeling for ourselves we are:

• • Free to figure things out and make massive changes as we go, even while using our model.

  • Free to neglect labeling because we know what each value is

  • Free to neglect structure because we know where everything is.

  • Free to use complicated, convoluted formulas because we know what they do.

  • Free to neglect data validation because we know what is and is not acceptable.

  • Free to correct errors while using our model because we know how to fix them.

All these freedoms spell disaster when modeling for others. When modeling for others we are:

• • Required to understand customer needs and define deliverables before work starts.

• Required to make models understandable by others with documentation, labeling, structure, and simplicity

  • Required to guide users to where they can enter assumptions and limit inputs to reasonable values

• Required to protect our model form inadvertent and unauthorized changes that could break our model.

  • Required to deliver error free solutions that simply do not break.

Neglecting any of these requirements can be disastrous. Deliver the wrong thing and we fail. Deliver something our customers cannot understand how to use and we fail. Deliver something customers can easily break, or breaks while being used and we fail.

To re-frame Percy C. Buck's excellent quote: A 'spreadsheeter' models until everything works, a professional until nothing can fail.

This course focuses on building models that cannot fail. But more than that, it shows how to improve transparency and efficiency while reducing complexity and risk. It also shows how to provide greater flexibility, scalability, and connectivity than traditional methods. These benefits grow in value as models become more complex and connected to other models, data sources, and people.

I'm an executive now, but started financial modeling for a small mortgage banker when interest rates in the US were double digits and loans using the rule of 78s created negative amortization. That was a long time ago. Computing was just becoming economically feasible for smaller businesses and VisiCalc, the first spreadsheet, hadn't yet hit the market.

VisiCalc changed everything. It introduced 'End User Computing (EUC)' enabling accountants, engineers, business analysts, and others to do what used to require coders. VisiCalc became the business modeling tool of choice. VisiCalc was limited. Only small models were possible. Over the years VisiCalc faded into oblivion and Microsoft Excel took over. Excel grew in power. Larger, more complex models were possible, but while Excel advanced, most modelers still modeled using the same methods pioneered in VisiCalc.

VisiCalc modeling still works but Excel's advanced features can do far more and far easier than VisiCalc ever could. Excel can pull data from other spreadsheets, databases, and the web. It can protect sensitive formulas from inadvertent and unauthorized changes. It can replace cryptic formulas with self-documenting references. It can compress an incomprehensible sea of data into readily understood at-a-glance charts. While we can still use Excel just as we did VisiCalc, we can do better with Excel's more advanced features.

To demonstrate what we can do, we will create a series of projects using modeling best practices that build on each other to eventually incorporate the core components of advanced Excel modeling: Data Validation, Conditional Formatting, Worksheet Protection, Names, Tables and Structured References, Power Query, and PivotTables with PivotCharts and slicers. We may even get a glimpse of Visual Basic for Applications (VBA).