Most leaders will tell you that it's lonely at the top. The pressure is high, the stakes are huge, and the need to appear in charge is paramount. So it's not surprising that top execs feel out on a limb and out of the loop.

That may be why the management consulting business is once again booming.

BusinessWeek estimates that management consulting is a $119 billion-a-year industry, and industry research firm Kennedy Information expects the market to grow as the economy heats up.

Companies and their leaders are creating strategies for growth, and consulting firms provide them with much needed guidance and expertise.

But consultants have their critics. Recent best-selling books have labeled consultants "false prophets" and "witch doctors." Fast Company magazine has a "consulting debunking unit" that regularly brings to task consultants who are creating buzz words and fads that, in their opinion, add little value to a business.

So how do you pick the right consultant? Bob Myers, Reebok International's chief human resource officer, said: "Consultants come in good, better and best skill sets. My rule of thumb is: Do your homework and make certain the consultant is truly an expert in the area where you need help."

It's an opinion shared by Scott Parker of PSF Advisors and former top executive at Gemini Consulting.

"There are obvious benefits to using a consultant to assist in strategic plan development when the consultant has deep industry experience or relevant experience in the issues currently facing that organization and others in its market," Parker said.

"A strong consultant can ensure that the lens is from the market and competitors' view, not vice-versa, and help senior executives avoid the market myopia that too often turns a strategy development initiative into an extrapolative business-planning exercise."

Consultants bring in objectivity, and there is real value in that outside perspective.

"Within the company it can be difficult to see the trees from the forest. Organizational bias and inertia limit out-of-the-box thinking," added Nirmal Pal, a Penn State professor and former top executive with IBM Consulting.

Myers agreed, adding: "Strategy building is something that few companies or executives become great at because it is done so infrequently so the process discipline is often weak. Good process and models from a consultant can free up managers to focus on the content and strategic linkages that will drive future actions."

But consultants have their limitations. Most consultants will never have the depth of perspective that senior executives have about the organization. That often makes consultants less aware of obstacles to an organization's ability to execute on their recommendations.

So how do you manage consultants to get what you need? Pal said you need "full executive support and commitment to the consulting team."

"Give the consultants access to key people within the organization," he added. "Have periodic status review meetings with the full team, more frequently with the engagement manager. That's how you shape and influence the outcomes and avoid surprises at the end."

Myers added: "Be precise about the deliverables up front. Be clear about the scale, scope and time frame of the project and the costs. But remember, companies employ consultants for expertise they don't have inside; so it shouldn't be a huge surprise if you learn something new that changes the nature of an engagement after you've started."

Parker boiled it down to a three-step checklist:

Select a consultant who brings the useful perspective and experience that you need.

Set the ground rules among the process-participating executives that the consultant will be playing a catalytic role that will require truth-telling and sometimes uncomfortable questions and assessments.

Contract with the consultant for a set of tasks within a mutually understood time frame that will produce results the organization can use productively to adjust course direction, speed and resource commitment.

There's an adage that two heads are better than one. That's especially true for leaders at the top of successful organizations. The decisions they make can have far-reaching consequences. Yet all too often, they make those decisions on their own.

With a little thought and careful guidance, consultants can provide useful input and guidance for a company's leadership direction.