I've worked with the major consulting firms, including McKinsey and their "usefulness" really depends on what you're asking them to do. My general rule is if y

I've worked with the major consulting firms, including McKinsey and their "usefulness" really depends on what you're asking them to do. My general rule is if you ask them to work on something external - say, a summary of a market you're looking to enter, they can be quite useful. You're basically hiring a team to work pretty much full time on a specific topic. They usually have a good network of experts to tap and can do the grunt work of talking to a wide range of people, access major data sources, and approach the analysis methodically. That can be sometimes tough to do internally if you have limited time, internal expertise and limited accesses to sources of info. Plus you can avoid internal bias in the analysis. If they are working on something internal to your company? Say org structure, new processes or policies? You may be disappointed. You as the internal person will know way more then they'll ever know and despite internal interviews and data collection, they'll have such limited visibility they'll likely give you some cookie-cutter answer. But if that's the cookie cutter answer you want to sell internally, have an outside, independent perspective is maybe exactly what you want.