Management Science: The Art of Modeling with Spreadsheets, 4th Edition

3 Spreadsheet Engineering

3.1 INTRODUCTION

Builders of ships, bridges, and skyscrapers all spend considerable time and money planning the structure before they order concrete and steel. Even the builder of a modest house starts with blueprints and a plan of activities. Without detailed planning, complex structures cannot be built efficiently, and they sometimes fail in use. The same is true of spreadsheet models. Spreadsheets can be as important to a business as bridges are to a road network. If a business relies on a spreadsheet, the business should devote sufficient resources to ensuring that the spreadsheet is suitably engineered.

Advance planning can speed up the process of implementing a complex design. Some years ago, the auto industry learned that investing more resources in preproduction activities saved a great deal of time and money when a new car was being prepared for manufacturing. One of the major sources of efficiency in this case was avoiding cycles of rework and redesign. Without good planning, the need for design improvements is detected only after implementation has begun, and much of the implementation effort is wasted. The same is true of spreadsheet models: extra time spent in planning can actually reduce the overall time required to perform a spreadsheet analysis.

Sometimes, at the outset, it seems that a spreadsheet project will be fairly straightforward. The flexibility of the spreadsheet environment seduces us into believing that we can jump right in and ...