As IBM's Environmentally Conscious Products (ECP) processes have matured, the subject of metrics selection has been recognised as increasingly important. The selection of appropriate metrics depends on what questions are asked of products and what type of products are involved. Metrics may be used to answer various questions:

• How do IBM products compare to other company's products?
  
• Are IBM products getting better with increased investment?
  
• Have products improved since previous generations (and by how much)?
  
• How does the environmental impact of one product line compare to another?
  
• Has the product met environmental expectations of customers?
  
• Has the product met IBM ECP policy targets?

The (ECECP) has worked with IBM's Personal Computer company, Networking, RISC/6000 and the Storage Systems Division to develop a metrics methodology. It was determined that these metrics would be used to:

• Provide feedback to product engineers and managers on eco-design requirements
  
• Benchmark, when applied to competitive products
  
• Document the environmental attributes of each product line to establish a reference point for future product design, and for information useful for marketing purposes eg. AS 400 has used this information to produce a green marketing brochure.

A rating method was developed which examines a variety of product attributes, each supported by design guidelines or targets. The scoring for each attribute is calculated from prescribed formulea, based on either a 'part count' or 'characteristic count' approach.

The part count approach:

The percentage of parts in a product meeting specific requirements eg. percentage of parts greater than 25 grammes labelled as per IBM specifications
.

The characteristics count approach:

Percentage of a given number feactures incorporated into the design of a product eg. features on 'design for disassembly':

• Minimum number of fasteners
  
• Accessible fasteners and components
  
• Common screw types and sizes
  
• Reusable components removable without breakage
  
• Can be assembled and disassembled without the use of special tools
  
• Reusable components accessable and removable without prior removal of lesser value components.

The rating methodology also allows for the inclusion of supplier ratings for ECP on product parts and components. These may include information of pollution prevention measures and reduction programmes and the use of chlorofluorocarbons (CFCs) by suppliers.

Each attribute is scored on a percentage basis, multiplied by a given weighting which reflects relative importance of the various environmental attributes, and summed to give an overall product ECP score. This metrics methodoligy is a recent introduction to IBM and will inevitably be modified with experience.