After leaving IBM in 1996 I founded a small Microsoft Office consultancy and software development company, Decision Models.

I specialise in providing Excel and VBA based departmental solutions, often with relational database backends.

My special interest areas are:
- Excel Calculation performance
- VBA UDFs & VBA Performance
- C++ XLLs
- Excel JS API 
- Large Excel models
- Excel Defined Names
- Excel as frontend to Relational Databases

I am co-author with Jan Karel Pieterse of Name Manager, a widely-used utility for managing Excel defined names, and author of FastExcel, a commercial product to help optimise Excel calculation speed.