No, the two root vegetables are not really interchangeable.
If you’ve ever scanned the produce aisle for some sweet potatoes, spotted a sign for yams, and thought, “Well, they're basically the same thing... right?” you’re not alone. While they’re often marketed interchangeably (most likely because of a somewhat similar appearance), the truth is, yams and sweet potatoes are very different root vegetables.
According to Chef Marc Bauer, master chef at the International Culinary Center, a yam is characterized by dark and sometimes rough skin, though the flesh is whiter in shade and dry. “Yams require more oil, cream, or butter when cooked and are generally more starchy than the modern sweet potato,” Bauer says. They’re also grown all over the world. Roast them with other veggies for a delicious side dish, dice them up into a hearty yam stew, or, if you’ve got a sweet tooth, try a batch of candied yams coated in butter and brown sugar
