We came upon an interesting blog posting from Stephen Gill regarding how easy it is to attribute cause and effect when so many variables can be at play.  He cites a book, The Invisibile Gorrilla which analyzes all sorts of "causal relatonships" between behaviors and events that happen at approximately the same time get linked by the human mind. The paragraph, from Stephen, that really caught our attention was this: 

Another area where leaders suffer from the "illusion of cause" is in judgments about the value of employee training and development programs. If there is no significant improvement in the performance of employees who go through training, the training is considered ineffective when, in fact, it could be a host of other behaviors and events that are barriers to learning and to learners applying what they learned.

Amen Stephen!  See his whole blog posting here: http://stephenjgill.typepad.com/performance_improvement_b/