That may be easy to calculate for assembly line workers in traditional manufacturing jobs once at the core of the economy. But it's far from the case for the service jobs and knowledge work that dominate [Businesses Registration]today's economy.

"When it comes to knowledge work, productivity is really hard to measure; it's nowhere near as simple as the number of bushels a worker picked in an hour or the widgets produced," says Lynn Wu, a Wharton operations and information management professor.

Wu points out that it would make no sense to judge the productivity of a software developer by counting the lines of code produced; a shorter string of code might yield a far better solution than a longer one.

Despite the difficulties, companies often end up relying on crude numeric tools, notes Matthew Bidwell, a Wharton management professor. Some rank engineers based on the number of patents awarded, for example. But who is more productive, the engineer who files many low-value patents, or one with fewer patents which prove to be more useful?

Moreover, Bidwell adds, such measures rarely take into account what he calls "citizenship behaviors" ? behind-the-scenes work such as recruiting, mentoring or communicating across teams.

Such behaviors are critical in knowledge organizations, yet they are frequently overlooked in favor of hard data. "The risk is that we focus more on quantity over quality, just because we can measure it,"[Hong Kong Company Formation & Registration] says Bidwell.

Facebook problem

Beyond measurement, another critical challenge is managing a workforce with varying levels of productivity. On any team, some employees will inevitably be more productive than others.

That was the issue Yahoo's CEO Marissa Mayer faced in addressing the firm's stay-at-home workers. Internal data showed that many appeared to be less productive than those working in Yahoo's offices, in part because many didn't log in to its virtual private network (VPN) for much of the day.

In the memo sent to employees, Yahoo's human resources director also argued that increasing face-to-face collaboration would improve the company's performance. "Some of the best decisions and insights come from hallway and cafeteria discussions, meeting new people and impromptu team meetings," she wrote.

While few management experts doubt the value of face-to-face communications in fostering ideas and collaboration, many believe Yahoo erred in addressing its productivity problem with a one-size-fits-all solution. By penalizing both high and low productivity employees equally, the company risks losing the strong performers among its telecommuters, without getting to the bottom of why others' productivity sagged.

"Blanket policies are a really bad idea to address performance issues" that involve only a few people, says Peter Cappelli, a Wharton management professor and director of the school's Center for Human Resources. "The right answer is to deal with those individuals."[company registration in Hong Kong, Hong Kong company incorporation]

Cappelli argues that managers should work directly with their low-productivity employees to determine the source of the difficulty and whether it can be resolved. "The biggest problem is a lack of supervision ? setting out objectives and following up on their progress," he notes.

In Yahoo's case, that might have meant only ending telecommuting for those who didn't log in to the VPN frequently. The laggards could have been more closely supervised from the office, while leaving alone those able to work productively from home.

To address Mayer's other concern ? her desire to improve Yahoo's performance through greater employee collaboration ? other, less draconian solutions might also have been found. Yahoo might have limited telecommuting to one or two days a week, Wu says.

Or it might have urged managers to schedule regular on-campus meetings or brainstorming sessions to foster more of the creative interactions Mayer sought.

Many companies have also turned to blanket solutions to address another common productivity problem: the fear that employees are spending too much time on personal e-mail, Facebook and other social networks. Once again, experts suggest that overly broad policies ? such as limiting Internet access for everyone ? risk doing as much harm as good.

Productivity punishment

Another difficult issue in managing a team with varying levels of productivity is balancing out the workload for those who boast better than average performance.

Consciously or not, these highly productive employees tend to become the "go-to" players: Managers know they can count on them to get a difficult or time-consuming project done.

And as staffing levels shrink even as the workload at firms continues to grow, the impulse to pile more projects onto the most productive only increases. It's a natural human tendency ? but it can also leave the most productive people feeling burnt-out. Employees quickly come to feel as though they are being punished? by being given more work? rather than rewarded.

The risk for managers is that these high-productivity people will leave. To counter that risk, managers must improve the productivity of other team members so that they can pick up more slack.