Cost professionals recommend only using the index back 5 years due to changes in technology, construction practices, labor efficiency, and formulation of the index.
Chemical Engineering magazine publishes the Chemical Engineering Plant Cost Index, which is widely used to quickly evaluate equipment and plant costs for the chemical and process industries. As of 2002, the index consisted of the weighted average of 41 PPIs (industry and commodity indices) and 12 labor cost indices, all reported by the BLS.