|This type of claim needs to be viewed with a large grain of salt. It is entirely possible that the training company's claim is accurate and their program did contribute to a reduction in turnover. Of course, it is also possible that their training program had nothing to do with it at all.|
All that can be said is that the training program was held, and turnover dropped after that. This does not mean that the training program caused the reduction.
Turnover could have dropped as a result of any number of other events occurring simultaneously. For example, the state of the economy tends to cause people to hold onto their jobs rather than quitting, and turnover can also decrease as a result of new leadership, changes in policies, improved working conditions, and the like.
At this point, the best step is to look carefully at your company's training needs, the specific objectives you would like the training program to meet, and the way in which the program focuses in these areas.
You should also probe into the techniques the training company plans to use to measure and evaluate the program's effectiveness. If the would-be trainers avoid these questions, you should avoid them.