Curt and Janice’s fight still rings in my ears. We were being inundated with calls complaining that our automated phone system was giving out bad account balances. Janice, the head of the phone system, was blaming Curt, the head of software development, saying Curt’s systems were giving her phones the wrong information. Curt fought just as loudly that the phone system was at fault. Janice had logs showing that the wrong information had been sent to her phone system, but Curt had just as strong evidence that the correct information had been sent. Who was right? Actually, the problem ended up being a faulty connection between the two. They were so busy worrying about their own pieces that they overlooked the interface.

In everything from computers to human communication, it is often not the individual elements that fail; rather, it is the elements’ interactions with each other — their interfaces. Therefore, managing these interfaces is crucial.

During the early 2000s, Steven DenBeste made a name for himself writing about technology on his blog, the USS Clueless. DenBeste often wrote about software development, and he more than once argued that a significant portion of a software developer’s role was to “manage the interfaces.” His observation was that while individual components of code might function smoothly on their own, issues most often arose when pieces needed to communicate with one another. I believe that this observation doesn’t just hold true for coding, but also extends to the broader dynamics of people and processes.

Consider this example: at work, a person finds a user-friendly web software for creating sales proposals. They download it, produce a series of proposals, and everything works perfectly. However, they soon find that they want all the data from this new system to also show up in their company’s accounting system. Because the systems don’t talk to each other, this data must be input manually. This is tedious work, and they will soon ask for this data transfer to be automated. Both the sales proposal software and the accounting system work fine and are bug free, but because they don’t communicate with each other there’s a problem.

Because this person was focused only on their immediate needs, creating sales proposals, and not on how this software would work with all the other software in the company, they made a decision that could become problematic. Getting two systems to work together is often much more work than simply setting up and learning each individual system.

Just think how tough it is to get people to coordinate. Take something as basic as an elevator ride. Each person enters, selects their desired floor, and waits. It’s a process so simple, and yet, often someone presses the wrong button, nearly exits at the incorrect floor, or boards an elevator going in the opposite direction. If such mishaps are a common occurrence in a context with straightforward rules, imagine the challenges of navigating complex environments. Collaboration in such settings demands both clear guidelines and regular practice.

The real challenge, and indeed the crucial role of managers, lies not in managing the people and the systems, but in managing the way they interact with each other.

When I teach about process, I often use a thought experiment that I call washer-dryer. When you are washing clothes, the entire process must be at least somewhat in synch. In other words, in order not to have wet clothes sitting around too long, it’s important that the dryer be available often enough to dry the clothes. If the washing machine is already as fast or faster than the dryer, then making it faster does the entire system no good as running the washer faster would simply mean leaving wet clothes around waiting for the dryer to catch up.

This is another example of where it is the interface that must be managed. The washer and dryer can both run perfectly and without defects, but unless they work together there will either be wet clothes or wasted time.

Businesses have many more moving parts and are much more complicated. If you have a washer and a dryer you have only one interface to manage, but interfaces increase exponentially with the number of things being interfaced.

And yet, in most corporate structures, leaders are judged based on the performance of their group and their group alone. Imagine if one leader had the washer and one the dryer, each trying to maximize performance. I can hear the washer owner now complaining about how the dryer isn’t getting things done fast enough and the piles of wet clothes lying around are all the dryer owner’s fault. If only they’d dry faster, things would be good.

The point is, focusing on the pieces is counterproductive. Effective leadership focuses on the interfaces. Leaders can best help counter this by working closely across the aisle with other leaders, and consciously focusing on how departments interact and communicate with each other. If you are a manager, think about which interfaces between your group and others work well and which don’t. Think about why each works or doesn’t work and focus some attention on those that don’t.

The most important piece of advice I can give about managing the interfaces is to pay them conscious attention. Most managers hardly even realize that the interfaces are there.