Why interface quality is impossible at scale

Good interface design becomes harder as software grows. Eventually, world-class interface design is impossible. Here’s why.

Too many relationships to manage

Good interface design is coherent. “Coherent” means the relationships between all of the things in the interface work well. But as the number of things goes up, the number of relationships goes up even faster. Eventually it’s impossible for people to properly consider all of those relationships.

This principle also applies to people. The more people who work on software, the harder it is to manage the relationships between all of them. Things are lost in translation. People disagree on the goal, and pull in different directions.

You can manage this with stricter processes. But eventually you’ll spend more time on process than on design.

Some people don’t care enough

The more people you hire, the more likely you are to hire people who don’t care enough about good interface design. Good interface design needs to be valued by everyone who can affect the work. That includes developers, designers, product managers, and often the CEO.

Some commercial goals hurt good design

If a company wants some numbers to go up for commercial reasons, this often hurts interface design quality. For example, adding more advertising to a website can help a company to become profitable. But it can also make the interface worse.

One way to grow is to add features that people request. But often each added feature makes the interface worse. This is hard to avoid, because of the first point above.