According to the World Health Organization, more than 1 billion people worldwide have a disability. To Astrid Weber and Jen Devins, Google’s resident accessibility experts, that stat should be stamped on the back of every designer’s hand, because it means that one out of every seven people on the planet is potentially left behind by thoughtless design decisions. At this year’s Google I/O conference in San Francisco, I sat down with the two UX experts and asked them what designers could do to make their apps more accessible. The key, they told me, was using your imagination and having a little more empathy. Here are six ways designers can reach that extra billion.