I've tried it three ways: having interviewees write code on paper, on a whiteboard, and on a computer.
Of the three, the computer fares worst. Many developers work in highly customized dev environments with special keyboards or monitor layouts. Using an unfamiliar setup, cold, in a stressful situation can make them sieze up or perform poorly.
Paper is no good because you can't watch their problem-solving process without hovering over their shoulder, and they get no feedback from you if they're going into the weeds.
The whiteboard seems to work best, because you get a good give-and-take effect between the candidate and interviewer.
Of the three, the computer fares worst. Many developers work in highly customized dev environments with special keyboards or monitor layouts. Using an unfamiliar setup, cold, in a stressful situation can make them sieze up or perform poorly.
Paper is no good because you can't watch their problem-solving process without hovering over their shoulder, and they get no feedback from you if they're going into the weeds.
The whiteboard seems to work best, because you get a good give-and-take effect between the candidate and interviewer.