y and Quality Principles 22.1 Business and Engineering Tools The biggest complaint about bad business decisions is that some key element was left out of the decision process. Therefore, business decision tools often focus on the process of defining the question and ensuring that no key factors are left out. One of these tools is total cost of ownership (TCO), developed by the Gartner Group. In the TCO model, all costs of developing, maintaining, and decommissioning a system are included in the cost of the system. For example, the total cost of an employee includes not only salary but also hiring costs, the employee's share of all overhead expenses (including the cost of the rental of the floorspace of the employee's cubicle), and all costs related to the em- ployee's retirement or departure. In recent years, TCO has been applied to information technology (IT) and telephony projects. In evaluating the cost of a new product or service, executives are requiring that project managers estimate the project cost; the operations, administration and maintenance (OA&M) cost for the life of the product or service; and the cost of decom- missioning. This is then annualized and offset against the value of the product or service. The primary value of a product or service is its effect on net revenue. If a change to cellular service is expected to bring in more money or reduce operating costs, then these contribute to the hard dollar value of the project. Hard dollar value denotes value that can be estimated and then measured. Businesses also recognize value that cannot be quantified and call it soft dollar value. Once we have defined the value and the TCO, we can calculate the return on investment (ROI). ROI is measured in months or years, and it is the length of time in which the amount invested in the new product or service, the TCO, will be recognized as revenue through hard dollar value. A project is clearly worthwhile if the ROI is under 1 year and worth considering if the ROI is 1 to 3 years and strong soft-dollar value 