Published estimating data is one of the tools and techniques for the PMI process to estimate activity resources. By using published data from sources such as books and industry journals, the team can use collected data to guide their estimates. For example, on a construction project an architectural or engineering reference text may provide rough information about how much of certain materials will be needed based on the size and type of the building. A guide from an entertainment journal could give staffing estimates for hosting a large event or conference. Similarly, published data can help estimate how quickly a set of people can complete a task.