How Too Much Multitasking at Work Can Slow You Down

At any given time, are you trying to juggle lots of projects at work? If so, you could be decreasing your output, recent research suggests.

Researchers Decio Coviello, Andrea Ichino and Nicola Persico studied a group of Italian judges who were randomly assigned cases and who had similar workloads, in terms of the quantity and type of cases they were assigned. The researchers’ findings? The judges who worked on fewer cases at a time tended to complete more cases per quarter and took less time, on average, to complete a case. These findings are described in the researchers’ October 2010 National Bureau of Economic Research working paper, “Don’t Spread Yourself Too Thin: The Impact of Task Juggling on Workers’ Speed of Job Completion.” (Coviello is a researcher at the University of Rome Tor Vergata in Rome, Italy; Ichino is a professor of economics at the University of Bologna; and Persico is a professor of economics and of law and society at New York University.)

However, that doesn’t mean all multitasking at work is inefficient. In earlier research into information-worker productivity in an executive recruiting company, Sinan Aral, Erik Brynjolfsson and Marshall Van Alstyne found that the level of multitasking matters. Their findings in that study suggested that, for the recruiters, working on more projects in one time period at first increased productivity, as measured by revenue generation. But as the level of multitasking increased, the marginal benefits of additional multitasking declined — and, at a certain point, taking on still more tasks made workers less productive rather than more so. (Aral is an assistant professor of information, operations and management sciences at New York University’s Stern School of Business; Brynjolfsson is the Schussel Family Professor at the MIT Sloan School of Management; and Van Alstyne is an associate professor in the information systems department at Boston University School of Management.)

Aral, Brynjolfsson and Van Alstyne essentially suggested that excessive multitasking may result in the work flow equivalent of a traffic jam, where projects get backed up behind other projects much the way cars get stuck in traffic when there are too many on a highway at once. (You can read a brief summary of their findings in “What Makes Information Workers Productive,” an article from the Winter 2008 issue of MIT Sloan Management Review.)