Management consulting is the business of solving a client's problem with a small, temporary, outside team. A consulting firm sends three to eight people to a company for a defined period, usually six to twenty weeks, to answer a question the company cannot or will not answer alone: why profits fell, whether to enter a market, whether to buy a competitor, how to cut cost without hurting growth. The team diagnoses the problem, recommends what to do with evidence behind it, and increasingly helps carry it out.

Three things make it different from a normal job:

• You are an outsider. You have no authority inside the client. Whether anything happens depends on persuading people who do not report to you.
• You are paid for time and expertise, not outcomes. Firms earn fees per project; their incentive is reputation and repeat work.
• You sell judgement. The tangible output is a model and a set of slides. The real product is the client's confidence to act on them.

Why companies hire consultants

Not because consultants are smarter than the client's own people. Four honest reasons:

1. Capacity. The client has the ability but not the bandwidth for a short, intense piece of work. 2. Expertise. A first acquisition, a first market entry, a transformation the firm has run fifty times elsewhere. 3. Neutrality. Internal teams are deadlocked, and an outsider can run a fair process. 4. Air cover. Leadership has a view and needs an independent, board-ready validation of it.

A candidate who can say this plainly sounds like someone who understands the job. One who says "companies hire consultants because they need smart people" sounds naive.

The skills the job runs on

• Structuring: breaking a messy problem into parts that do not overlap and leave nothing out.
• Hypothesis-driven work: forming a view early and testing it, rather than collecting all the data and hoping a story appears.
• Top-down communication: answer first, then the reasons.
• Numbers on the fly: back-of-envelope maths that is roughly right, in the meeting.
• Client handling: reading the room, raising concerns before they become objections.

The case interview tests exactly these, which is why it is the interview.