Robert Half knows a thing or two about ability. He founded Robert Half Associates, today a $4.7 billion global provider of talented staff through its seven industry-focused divisions. RHA was again ranked this year among Fortune's Most Admired Companies, tops among staffing companies.

Half once observed, "There is something much more scarce, rarer than ability. That is the ability to identify ability." Determining who has the right ability (the set of skills, knowledge, talent and experience) to match a particular role or position is the purpose of the hundreds of millions of job interviews conducted each year.

Hiring people with the right ability is just the first step. Being able to focus and develop that ability is a key objective of the new hire's manager.

I'd like to amend Half's ability maxim: "There is something much more scarce, rarer than ability. That is the ability to identify ability. But the rarest and most valuable ability of all is the ability to develop ability in other people." The person who can develop the people around him or her is perhaps the most valuable person on any team.

Being indispensable is counterintuitive

"Mary," I said, "your prime directive here is to train and coach your staff to be able to do their jobs so well they can function perfectly even when you aren't here. Even if you are away for several weeks at a time."

"But, boss," Mary said, "if they are able to do all their work without me here, then why would you need to keep me?"

Many managers and leaders think that being indispensable results from becoming the key go-to person for the decisions in their areas of responsibility. They see themselves as indispensable when every staff person comes to them to tap their expertise to solve problems, work through challenges and make difficult decisions. Employees literally get in queue to speak to them.

That is not being indispensible at all! That manager or leader has become the small end of the funnel through which the entire business of the department or organization has to flow. That means the overall productivity is limited by that manager's capacity as the small end of the funnel.

At some point, senior leadership or the board will observe this and ask the logical question, "Why aren't this manager's people making their own decisions? What has the manager done to create a self-directed staff?

Become indispenable by being dispensable

How does a manager become indispensable to his or her organization? By assuring the right individuals are on staff, then developing each one to be able to operate for periods of time without the manager's direct supervision.