Apple's new laptops have been generating complaints about the battery meter. The "time remaining" display has a bad habit of jumping all around and not giving the user meaningful information about how much time they can actually keep using the computer.
Getting this display right is a tricky problem, and it's a nice simple example of a situation that's common to a lot of dashboards and data visualization. The challenge is that you are trying to communicate a relatively simple and actionable message with a very complicated underlying system, where the person receiving the message isn't an expert and can't be expected to become an expert.
In the case of Apple's battery meter, the user wants to know roughly how long he can keep using the laptop before plugging in. But the complicated reality is that the laptop's power usage can vary second-to-second, and it's not always obvious what's driving the changes. You may be happily surfing the web and barely sipping the battery, but should you visit a page with a lot of animations (or worse--scripts to track your web viewing and serve you ads) that suck up the CPU, your battery usage will spike and time available will plummet.
Juice Analytics took a look at this problem recently, and provided some different ways to better communicate the nuances of laptop battery life. In all likelihood, none of the options will be completely satisfying to the typical user who just wants to know if he has enough battery to watch The Matrix to the end.
But just like in the business world, where leadership may want simple answers to complex questions, sometimes it does a real disservice to give people the data they think they want. The challenge is to find a simple way to communicate the data they actually need.