The term yokoten refers to the sharing, learning and teaching of best practices laterally throughout an organization.  Yokoten is often referred to as "horizontal deployment" because practice of this principle requires various levels of an organization to share, innovate spread knowledge and or improve on kaizen in a cross functional manner.  A very important aspect of this critical principle is that individuals have an opportunity to exercise Genchi Genbutsu and gain consensus on improvements.  At times yokoten can include benchmarking, comparing and even borrowing from other improvements, but, in the truest sense yokoten should allow people to develop and grow as a result of sharing, learning and teaching.  

  This is the core equation used in six sigma.  The Y is the dependent output, the X is the independent inputs and f represents some process or functions application.  The greek symbol ε represents some degree of error or uncertainty in the process.