OK, let’s talk just a little more about FLOW and then I’ll move on.
Back to the airport. You and 9 friends are traveling somewhere – let’s say Florida (get it…flow-rida?!). You have to go through ticketing and security.
If it takes each of you 6 minutes to go through ticketing, then ticketing 10 people takes 60 minutes, or 1 hour. Imagine the same for security – on average it’s 6 minutes a person and 1 hour for the group. So in total, 10 people will move through ticketing and security in 2 hours.
If you use a batch size of 10, you will all be through ticketing after 1 hour. Total throughput – people inside the gate – will be 0 after 1 hour.
If you batch size in 5, then this smaller batch is through ticketing in 30 minutes. In another 30 minutes, they’re through security. After 1 hour, total throughput is now 5.
Plus, once those first 5 people get through ticketing, you would obviously send the other 5 people into ticketing right away. So actually, after 1 hour, you would have 5 people in the gate and 5 people through ticketing. Once those last 5 then move through security, you will have all 10 people in the gate within 1.5 hours. Compare that to 2 hours for the 10 person batch size.
Breaking down into individual batches – a batch size of 1 – moves even faster. For the first 6 minutes, 1 person is being ticketing. Every six minutes after that should have 1 person being ticketed and 1 person being security checked. Everyone will be through the system in 6 + 9×6 + 6 minutes, or 66 minutes. Just over 1 hour.
Smaller batches – they move faster. Improve your flow on any project by reducing batch size.