In South Korea, the Business Survey Index (BSI) in the manufacturing sector measures the level of optimism that business leaders have about the performance of the economy in the current month and their outlook for the following month. The Index is based on the survey of around 2800 companies in fifteen areas including sales, inventories, production facilities, prices, labor force and profitability. For each of the indicators measured, the net difference between the number of positive responses and the number of negative responses is computed. The BSI above 100 indicates an improving outlook and below 100 a deteriorating outlook.