Product design specification

A product design specification (PDS) is a statement of what a not-yet-designed product is intended to do. Its aim is to ensure that the subsequent design and development of a product meets the needs of the user. Product design specification is one of the elements of product lifecycle management.

The PDS acts as an initial boundary in the development of products.

PDS vs. product specification
The PDS is a specification of what is required but not the specification of the product itself. Describing the actual product is done in the technical specification, once the product has been designed. The difference is important since describing the product itself at the stage of creating a PDS, effectively constrains the range of alternatives that are considered during the design process.

The distinction can be seen as the difference between "What does the product do?" and "How will the product do it?"

PDS vs. design brief
The PDS evolves from the design brief. While the design brief outlines the design goal and major constraints and considerations, the PDS goes further to determine the precise limits for the full set of requirements in the product being designed.