If I handed you a book about how to surf, could you read it and then jump in the water and start carving waves? Of course not, the way you learn to surf is by surfing.
Let's change this example to something a little more relatable to law enforcement...like riding a bike. When you are a training unit, you have your field training officer with you. That officer will (hopefully) prevent you from making a huge mistake like arresting the wrong person or kicking in the wrong door. You are riding a bike but for now, your bike has training wheels. When you are done with field training, you get take off the training wheels. You're still shaky but you're on your own. NOBODY would expect you to do the things on a bike that guys that have been riding for years and years can do. See? There are 3 stages of proficiency with pretty much everything you. When you start off, you hope to get FAMILIAR with your craft. After some time, with a lot of work, you hope to become SKILLED. Finally, after you've been doing it for a long time, when you are a student of the game/ craft, you become an EXPERT.
Sadly, many law enforcement agencies are dealing with commanders who are in charge of many patrol officers, when they have an embarrassingly small amount of ACTUAL patrol experience (for Tucson PD I'm talking about Adam units, X-Ray units, or U-Units) .
I'm just getting started with this story, give me some time and I'll post some documentation that will be embarrassing for many. Stay Tuned!!