I meddle with learning curves from time to time and you can imagine my delight when I found that the very famous Charles Babbage published a book in 1832 in which he gave an example of learning curves in action. I have incorporated that example in my own learning curves presentation, for your delight! It's a PowerPoint Presentation so may be a bit slow to start with. You can ask for the speaker's notes to go with it too, by clicking on the email link on the final slide. DW