The Basic Materials Sector is an important part of the economy, and companies within this sector play a vital role in supplying raw materials for construction and other industries. The sector is sensitive to changes in the business cycle, and usually does well when the economy is strong. Within the sector, there are companies that specialize in mining, metal refining, and forestry products. These companies provide the majority of materials used in construction, making them sensitive to changes in the economy. When the economy is strong, they usually thrive.