My standard approach to the "determining their depth" problem is to give them a problem where detailed knowledge provides an obvious (or perhaps more elegant) a

My standard approach to the "determining their depth" problem is to give them a problem where detailed knowledge provides an obvious (or perhaps more elegant) answer, but there are other possible answers. For example, "how would you implement a least recently used cache in Java" can provide a wide array of answers and tells me a lot about the person's knowledge of the SDK and overall algorithm design. The details of their solution and the ensuing discussion tells me a lot more, no matter what their level, than whether they simply know that LinkedHashMap.removeEldestEntry exists.