As the economy improves in the months ahead, companies will have to begin hiring to keep up with increases in demand. At the same time, top performers are feeling less loyalty to their employers.

Consider some of the recent research. Sibson Consulting reports that one out of six employees is ready to bolt. Walker Information says its survey of 2,400 employees found that 34 percent were at high risk for departure.

Other experts predict that annual voluntary turnover could rise to 20 percent or more for white-collar workers, as companies compete for the best workers. And Accenture says half of all U.S. middle managers are either seeking new jobs or planning to do so in the near future. All of this means that companies must do everything they can to keep their best people.

Many industries will face shortages of workers. Analysts expect a nearly 70 percent surge in the workforce for the health-care industry during the period from 1998 to 2008. Within 10 to 15 years, there will be a nursing shortage that will leave one in five positions unfilled.

Another industry expecting huge growth in its workforce is the computer and data processing services industry. By 2008, it will need 1.8 million more workers — an increase of 117 percent from 1998.

Industries that have downsized because because of the economic downturn are not going to be immune from the need to hire more workers, either. While many manufacturing firms have been operating in layoff mode over the past year, that’s about to change. A new study of 600 U.S. manufacturers found that two-thirds of them are suffering from a moderate to serious shortage of qualified machinists, operators, craft workers, technicians/electricians, and engineers.

We can see an historical precedent for this trend by looking back to the recession of 1990 to 1991. When the job market exploded in 1992, turnover soared as workers switched employers. The difference this time around is that the tight job market of the most recent recession has been more extensive and has lasted longer than the one of 12 years ago. As a result, more people are waiting for the right moment to switch jobs — and that moment is coming soon.

And who’s going to be rushing to hire all of these people? You, your competitors, and companies in other industries who can use the same basic sets of skills. This new, high-turnover...