It's extremely helpful if a team member has a CS degree, but it's not always essential. The CS grad usually understands the whole stack from UI through CPU, I/

It's extremely helpful if a team member has a CS degree, but it's not always essential. The CS grad usually understands the whole stack from UI through CPU, I/O, and memory. They don't get the distant stare when they see code with a Red black tree or a graph algorithm. They may not know about skip lists and bloom filters, but they can figure it out quickly. They understand reference vs. object equality. They understand multi-threading and concurrency strategies. They understand how to implement a hash so that there are few map collisions. That said, a lot of IT work, web development work, database work, API work, etc. doesn't require all of that. A lot of my work does, but if it doesn't, I hire based on passion, productivity, resourcefulness, and craftsmanship. As an analogy, many small businesses are successfully run by self-taught entrepreneurs. But, running a $100M company requires different knowledge.