The triple whammy – away from work, not billable, and it cost money. This has always been a sore spot for firms that are thinking of earning and saving money (and who isn’t). Since you have to dedicate the time to training it take you away from being productive and contributing to the project (on the short term). You also are not billable when you are in training since you are not contributing to the project deliverable. And finally it cost money to send you to training. If the trainer is an in-house employee, you are paying their salary. If they are on the outside, you pay for their time of a flat fee per student.
So how do you minimize the Whammy?
Carve it out in small chunks.
Keep the classes short and sweet. Lunch ant learns during the mid day break. Two hour sessions or four hour sessions allow people to contribute to project work. These short sessions also break learning into more palatable portions. No one is trying to learn too much at one time.
Keep it focused
Shorter classes mean better focus on one topic. By staying on topic the learning is drilled into the learner. No confusion related to multiple concepts or tasks.
Make it valuable
Give them handouts. Something to take with them. Do it hands on if possible. Follow up after the class to see if people are using what they learned.
Make it stick
Training sticks if you make it stick. By constantly reminding people of the new methods and tools you stand a chance of making progress. If you just train them, push them through class and never reinforce what they have learned, you most likely will not see advances made.