One of the things we clicker trainers must do is see behavior and be timely. Obviously we want to be as accurate as possible, so the dog knows what we are trying to say with our clicks. There's always a lag time and while some people are able to click in under one-tenth of a second (you know they are playing a lot of computer games), the average person is going to be .215 seconds late.
This is because your brain has to process what you see and then there is still, on average, a .130 second lag time between the decision to click and the time it takes for the nerve impulse to go from your eye, through your brain to your thumb. One of the reasons we use a clicker is because it is so much faster (and thus more accurate) than the significantly longer time it takes to say a click-word. That impulse has to travel from you eye, through your brain, through the speech center of your brain, then to your mouth and finally for all the parts of your mouth, tongue, vocal cords and breath to come together and form a word.
If you want to know how fast your reaction time is, you can click on this link: Reaction Time Test I found out that I'm completely average and indeed came right in at 215 milliseconds.
The good news is that we can improve our time by carefully watching our dogs, because as you become familiar with how your dog moves and behaves, you can predict that clickable moment. In any case, the clicker gurus all agree that in terms of the final result and how long it takes to get there, its always better to click early, rather than late.
So what's your score?