and press the button on top of the productivity clock so that it starts counting time on the idle clock. This is because you first arrive at work and do things like say hello to people and organise your desk from when the cleaners came through and messed everything up. This isn't productive.  You will know when this is. Note this in a log. You can even work out the percentage of time wasted. 
Get to work quickly Press the button on top of the idle clock so it starts the counter on the productivity clock. Keep it that way until you think you've stopped being productive. At the end of the day you will have a precise measurement of both productive and idle time at work. You should remember to reset the clock for the next day upon deciding to begin the journey from Work to your Home.