More on Computer System Responsiveness

Why do sub-one-second response times make us more productive?

Last time in this space, I mentioned an IBM research article that indicated that IT workers can be dramatically more productive when using computer systems with very fast response times. In a study of programmers, IBM found that system response times of 0.3 second more than doubled programmer transaction output compared to response times of 3 seconds. This was contrary to the conventional wisdom, which said that computer system delays are really not so bad because they give information workers time to think about their next task.

The interesting question becomes, why does decreasing system response times have such a beneficial impact on productivity? I have a couple of theories and I thought I'd float them by you. (You may have some ideas of your own, too, and if so, please comment.)

First, I don't think information workers *need* a lot of time to think about their next task in many cases. We often know what we want to do and we know the steps we need to execute to get there. So the benefit of a computer-imposed pause may be illusory in such cases. Second, I think the human mind starts to wander a lot more quickly than we might at first suspect. After a few milliseconds of inactivity, we start to think about other things, if only subconsciously. Then, when the computer system is ready for us again, we have to shift gears back to the task at hand. In system design, they call that "context switching." I'm sure it's just as inimical to productivity in humans as it is to silicon processors. Third, I suspect that people tend to be more productive when they can get into a rhythm. However, you can't get into a rhythm when using an information system that presents randomly varying delays, especially if those delays are long enough for our minds to wander, and if we already have a good mental roadmap of which tasks we need to perform next.

Of course I'm no psychologist and all of the above is speculation on my part. What do you think? Is computer system responsiveness more important than we may have thought?

• Microsoft
• computer responsiveness
• productivity
• response time
• Server 2008
• Windows 7