How to measure the training efficiency

This is just a thought that I was having on informal and formal learning,.
You might decide that having the learners "informally" learn a task is more efficient than "formal" training, but according to Carnevale, Gainer, & Villet's , "Training in America: The Organization and Strategic Role of Training," formal learning is about three times more efficient than informal learning. Now they don't break down the numbers, but consider this -- Allen Tough, a Professor Emeritus at the University of Toronto, who was one of the thought leaders on informal learning, discovered that within each informal learning episode (where the primary motivation is to gain and retain certain knowledge and skills on a task), the average learner interacts with an average of 10 people.Thus rather than informal learning being a solitary act, these learners are interrupting the daily activities of their coworkers as they seek advice and coaching. So now you might think it is more efficient to actually create the training program, rather than have them learn it informally.But consider this -- a large piece of research on informal learning was produced by the Education Development Center (EDC) in 1997. This was a comprehensive two-year study funded by the US Department of Labor and the Charitable Trusts. It included companies such as Boeing, Siemens, Data Instruments, Ford and Motorola. When observing operations at the Motorola Company the researchers calculated that each hour of formal learning spills over to four-hours of informal learning or a 1:4 ratio. It seems informal and formal learning is implicitly tied together.So now depending on how many "episodes" of informal learning are in your formal training program, you have now potentially exaggerated the savings you were hoping to achieve as the spill-over to informal learning could erase it all with its inefficacy and disruptions to the rest of the workforce!Yep -- calculating "efficiency" is a piece of a cake!