The Well-Tempered Spreadsheet is dedicated to raising the quality and efficiency of financial analysis. Topics will include modelling tips and mathematical insights.
Win Smith is the author of The Well-Tempered Spreadsheet. His career has centered on quantitative finance but has many facets: programmer, modeller, analyst, teacher, mathematician, inventor, investment banker, financial advisor, CFO and expert witness. Mr. Smith holds an MSc in Mathematical Finance from Oxford University. His Master’s thesis was “Robust Bond Portfolio Optimization.” He also won the Anthony Stanley prize in mathematics as an undergraduate at Yale University.
Mr. Smith is a Data Scientist at Wells Fargo. He was previously President of Win Analytics LLC, an independent research and advisory firm.
The Name of the Blog
The name of this blog alludes to Bach’s Well-Tempered Clavier, which illustrated the versatility of a newer tuning system with keyboard pieces in all major and minor keys. It is “generally regarded as one of the most influential works in the history of Western Classical Music.”
I may have been inspired by all the Bach we play in our house, or by the fact that my uncle, Jack Treynor, was called the “Bach of Finance.”
Musical keyboards and spreadsheets have some similarities. Their arrays of keys or cells can be manipulated to create either junk or magic. It’s easy to jump right in and pound away, but what does it mean to do it well? I’ve confronted that question for many years, in both cases.
This blog is about financial modeling and math. It will not be confined to spreadsheets: more powerful tools will also be discussed. But “The Well-Tempered MATLAB” doesn’t have much of a ring to it, and “The Well-Tempered Model” sounds like a rarity in Milan.
The Well-Tempered Spreadsheet 
Hello, I have used your website for a great deal of research and it is an EXCELLENT resource. i have an issue I am struggling with understanding. As it relates to Weighted Average Life, I have seen this defined many ways from many sources. Some say it is the average time for a dollar of principal to be repaid/(or remain unpaid) and others say the WAL is the number of years until the principal is paid. This seems to be conflicting to me. I read on a reputable website that if you calculated WAL of a 30 year fixed rate mortgage to be 20 years, that is equivalent to a 20 year bullet. I don’t full understand how that is. The bullet will be paid off in 20 years however the principal balance on the mortgage wont be paid of in 20 years. 20 years is just the average time of time principal remains outstanding. I truly appreciate you clearing this up for me. It means a lot to have your time. I also am having trouble going from a CPR to WAL, I have been taught 1/CPR = WAL. Which seems to be true however when I use that same methodology to convert SMM in WAL and then divide by 12 months. I get a lesser WAL.
Again thank you so much for your time!
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