This is an article by Marcus Buckingham, best selling author and thought leader.

What sets a great boss apart from an average boss? Research on this is rife with provocative writing about the qualities of managers and leaders and whether the two differ, but little has been said about what happens in the thousands of daily interactions and decisions that allows managers to get the best out of their people and win their devotion. What do great managers actually do?

In our research, beginning with a survey of 80,000 managers conducted by the Gallup Organization and continuing during the past two years with in-depth studies of a few top performers, we’ve found that while there are as many styles of management as there are managers, there is one quality that sets the best managers apart from the rest: they discover what is unique about each person and then capitalise on it. Average managers play draughts, if you like, while great managers play chess.

What does the chess game look like in action? When I visited Michelle Miller, the manager who opened Walgreens’ 4,000th store, I found the wall of her back office papered with work schedules. Miller’s store in Redondo Beach, California, employs people with sharply different skills and potentially disruptive differences in personality. A critical part of her job is to put people into roles and shifts that will allow them to shine - and to avoid putting clashing personalities together. At the same time, she needs to find ways for individuals to grow.

A manager’s approach to capitalising on differences can vary from place to place but it is a tremendously powerful tool that leads to three outcomes. First, it saves management time; second, it makes each person more accountable; and third, it builds a stronger sense of team because it creates inter-dependency. It helps people appreciate one another’s particular skills and learn that their co-workers can fill in where they are lacking.

When you capitalise on what is unique about each person, you introduce a healthy degree of disruption into the workplace. You shuffle existing hierarchies, existing assumptions about who is allowed to do what, and existing beliefs about where the true expertise in a company lies. These questions will challenge the orthodoxies of companies like Walgreens and help them become more inquisitive, more intelligent, more vital and, despite their size, more able to duck and weave into the future. At some point, however, managers need to rein in their inquisitiveness, gather up what they know about a person, and put the employee’s idiosyncrasies to use. To that end, there are three things you must know about someone to manage them well: their strengths, the triggers that activate those strengths, and how they learn.

Great managers spend a good deal of time outside the office walking around, watching each person’s reactions to events, listening, and taking mental notes about what each individual is drawn to and what each person struggles with. There’s no substitute for this kind of observation, but you can obtain a lot of information about a person by asking a few simple, open-ended questions and listening carefully to the answers. Two queries in particular have proven most revealing when it comes to identifying strengths and weaknesses.

To identify a person’s strengths, first ask: “What was the best day at work you’ve had in the past three months?” What were they doing and why did they enjoy it so much? Remember: a strength is not merely something you are good at. It might be just a predilection, something you find so intrinsically satisfying that you look forward to doing it again and again and getting better at it over time.

To identify a person’s weaknesses, just invert the question: “What was the worst day you’ve had at work in the past three months?” Probe for details about what they were doing and why it grated on them so much. You might be quite competent at a weakness but it drains you of energy, you never look forward to doing it and when you do do it, all you can think about is stopping.

Although you’re keeping an eye out for both strengths and weaknesses, your focus should be on an employee’s strengths. Conventional wisdom holds that self-awareness is a good thing and that it’s the job of the manager to identify weaknesses and create a plan for overcoming them. But research by Albert Bandura, the father of social learning theory, has shown that self-assurance (labelled “self-efficacy” by cognitive psychologists), not self-awareness, is the strongest predictor of a person’s ability to set high goals, to persist in the face of obstacles, to bounce back when reversals occur, and, ultimately, to achieve the goals they set. By contrast, self-awareness has not been shown to be a predictor of any of these outcomes, and in some cases, it appears to retard them.

Always remember that great managing is about release, not transformation. It’s about constantly tweaking your environment so that the unique contribution, the unique needs, and the unique style of each employee can be given free rein. Your success as a manager will depend almost entirely on your ability to do this.