Bigger is better in monitors — to a point

Computerworld - Bigger can be a bit better than more when it comes to monitors, but for worker productivity, there's a point where big is too big and any gains flatten out, a researcher said today.

Although it's accepted wisdom that multiple monitors boost productivity, computer users looking at a single, larger display actually get more work done in the same amount of time than those staring at a pair of somewhat smaller screens, according to James Anderson, a professor of communications at the University of Utah.

In a follow-up to a 2003 study that tested how long it took people to edit a word processing document or a spreadsheet worksheet using single- or dual-display systems, Anderson timed the same chores for users facing two 20-in. LCDs, one 24-in. screen or one 26-in. display.

Users working with dual 20-in. screens boosted their performance by 44% in text editing and by 29% in spreadsheet editing over a single 18-in. monitor, said Anderson. With a single 24-in. LCD, the same tasks showed performance gains of 52% (text) and 26% (spreadsheet) over one 18-in. monitor.

But when Anderson asked people to finish the same editing tasks on a 26-in. monitor, performance actually dropped in the spreadsheet chore.

"When you have multiple windows open, the more desktop space you have, the more material you can handle," said Anderson. "It's not brain surgery." But there does seem to be a point where adding more screen real estate doesn't produce much, if any, gain in productivity. The graph, he noted, ends up looking like a Bell Curve.

"I think it's the overhead of the task," he said when asked to explain why moving to a 26-in. monitor didn't translate into a productivity increase. "There's a [time] overhead spent managing windows and adjusting them on the screen," he said. When LCDs get larger than a certain size, the overhead takes a toll.

The sweet spot, then, is a dual 20-in. setup or a lone 24-in. screen.

"The worst, by far, is a single 17-in. [display]," Anderson said. "If American companies replaced all their 17-in. monitors, they would see a significant increase in productivity across the board." Anderson cited statistics that claimed some 19 million 17-in. screens are still being used by American businesses.

Those gains, and the resulting cost savings, could be considerable. A company with 250 computer-using workers would see a net annual savings — after the cost of the monitors and higher utility bills to power the larger displays — of $2.3 million by swapping their current 17-in. monitors for single-screen 24-in. configurations, or save $1.6 million if they went with dual 19-in. displays.

Those figures were predicated on a nonstop eight-hour day, however. "No one works eight hours straight," Anderson said, acknowledging that the posted savings are on the optimistic side.

Monitor and computer maker NEC Corp. funded the study, but Anderson defended its independence. "All they provide is the money," he said, adding that like all research at the university, the study was vetted by the school's research board.

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