Why It’s So Hard to Figure Out Whether Health Apps Work

The phrase there’s an app for that has gone from stunning claim to cliché to fact of life. We use apps for everything from finding romantic partners to safeguarding our health to getting an eyeglasses prescription. But when it comes to health-related apps, whether they claim to treat depression or diabetes, determining what is effective is often difficult. That’s troublesome, because therapeutic apps have enormous potential to reduce the cost of health care—if only we can determine whether they work. Like everything else in health care, determining the impact of an app requires rigorous, well-planned studies. And that brings us to one of the field’s biggest challenges: It’s really hard to come up with a placebo for...