The lean concept of pull is an extension of flow.
Within flow, we’re trying to eliminate excess inventories and places where the product stops moving. The idea is to get an entire value stream continuously flowing.
So, what drives the flow of the value stream?
The customer. Customer demand is what makes the value stream flow. The customer literally pulls value from the value stream, which then replenishes itself.
Pull, at its most elemental level, is the idea that you shouldn’t overload your downstream colleagues with work if they don’t have the ability to handle it. Instead, the downstream colleague should “pull” or request the next piece of work to be performed. In so doing, the entire value stream moves along. Ultimately, the customer is the one who initiates the pull through the value stream and all of the subsequent handoffs are simple replenishing that which the customer has taken.
Why is the concept of pull important?
One key reason is because most of us are accustomed to batch processing as the most efficient means of production. The problem with batch processing is that you are essentially guaranteeing that the person downstream of you will get overloaded with work. When that person gets overloaded, lead times go up, quality goes down (given the tendency to rush to clear a backlog), and the entire thing takes significantly longer.
What’s true manufacturing is also true in the office, though it’s less visible.
You see this with email all of the time. Lots of productivity gurus advise you to batch process all your emails. However, this batch processing may work for you–but what does it do to all of the colleagues downstream of you. Especially if you work with one or two colleagues more than others, you are almost certainly burying them in emails, which means your email will likely not be responded to or be responded to significantly later.
If your “productivity system” hurts the overall productivity of your work colleagues in your value stream, it’s not productivity at all–it’s the opposite. Don’t be surprised when things take longer to get done.
An ideal email processing system would be one where it was impossible to send an email if the recipient didn’t have capacity for it. Sounds crazy, right?
But what’s much crazier is continuing to bury your colleague with work they can’t handle.
Imagine if you couldn’t send an email unless your colleague had capacity. What would you do if you needed to send them an email? Well, you may call them up and say, “Hello, Robert, I noticed you are at maximum capacity. Is there anything I can do to help you out, as I’ve got an important topic I need your assistance with.”
This sort of helpful approach is precisely what happens in lean manufacturing all of the time, and it’s time that this approach made it to the office as well. The flexibility of the value stream to move beyond the bounds of harsh and bound demarcations of roles and responsibility and instead to focus on value creation for the customer (and overall organizational throughput) is a sign that the organization has adopted a true lean mindset.
Plus, it’s good manners.