A lot of attention has been paid to the role of algorithms in shaping the experience of consumers. Much less attention has been paid to the role of algorithms in shaping the incentives for business decision-making. Understanding how to evaluate algorithms without knowing the exact rules they follow is a key discipline in today's world. And it is possible. Here are four rules for evaluating whether you can trust an algorithm: Its creators have made clear what outcome they are seeking, and it is possible for external observers to verify that outcome. Success is measurable.