Kosu It's a productivity indicator obtained by dividing the total worked time by the number of pieces produced. It' one of the principal's indicators to measure productivity. In more details: Kosu is a means to learn about the real cost of products in real time. KOSU is the unit of time spent for each product. All the direct costs (in terms of time spent) are taken into account, even additional hours. Time is attributed to each product. KOSU is measured at a workshop level. KOSU is the main productivity indicator.