Which type of specification allows contractors to choose how to achieve the required results?

Performance specifications are designed to outline the desired outcomes or results of a project without dictating the methods or materials that must be used to achieve them. This approach gives contractors the flexibility to determine the means and methods they prefer, fostering innovation and potentially reducing costs. By focusing on the end results rather than the process, performance specifications encourage contractors to utilize their expertise and creativity in finding the most effective solutions to meet the project requirements.

In contrast, proprietary specifications restrict choice by naming specific products or methods that must be used, while descriptive specifications provide detailed descriptions of materials and methods to be followed. Reference specifications typically provide standards or guidelines from recognized organizations but may not allow vendors to diverge from established norms.

Thus, performance specifications are particularly valuable in projects where innovation and efficiency are desired, making them the best choice when contractors are allowed to determine how to meet the specified requirements.