When it comes to learning and growth of the employees of any company, it is hard for a measurement to be taken. Effective training can be and objective that can be extremely hard to measure. Each employee learns at a different rate some can pick something up after just a few minutes others need weeks to grasp the same thing. Just because some people do not learn at the same rate, does not mean that the training is not working it just means that it failed for just that one person.
Developing training for all types of learners is a start but it still does not guarantee success.
Please propose a metric that could be used to quantify the above statement.