The Bureau of Labor Statistics (BLS) is an independent statistical agency that measures and reports labor market activity, working conditions and price changes in the economy. As the BLS collects, analyzes, and organizes the essential economic data, they also compile reports such as Consumer Price Index (CPI), changes in unemployment, wage data, productivity data, and the Producer Price Index (PPI). The BLS developed projections of the industry and occupational employment through six interrelated steps or models: labor force, aggregate economy, final demand (GDP) by consuming sector and product, industry output, industry employment, and employment and openings by occupation.