Control Sensitivity in Design

I run into the problem everyday: when I try to adjust the temperature of my shower, it is just way too sensitive. I have to move the lever as carefully as I can, however, it still surprises me with sudden change of temperature. I end up taking a shower either too cold or too hot.

This occurs to me today because I read about “control-display ratio” today when I went over the human factor class that I am taking this semester. Control-display (C/D) ratio is measuring the change of control compared to the change of display (or outcome, response). If the C/D ratio is high, then the control sensitivity is low, and vise versa. C/D ratio is very important for HCI design as well. Low C/D ratio (high sensitivity) could save time when users are approaching the target, while high C/D ratio (low sensitivity) could help user with fine adjustment when they reach the target area. So a carefully designed C/D ratio is important for improving user controlling experience. For example, the movement of mouse or controlling stick should have a reasonable C/D control so that users could minimize the effort when they try to move their mouse to reach a target.

The following is a common example in our everyday life: when you try to adjust the window, cursor has to be moved within a narrow area in order to change the shape. If the control sensitivity is too high, it will be very very annoying.


One thought on “Control Sensitivity in Design

  1. Mihaela

    Excellent observation about how control sensitivity needs to vary on the computer interface depending on how close you are to the target or action.

    About your shower, it sounds like you need to call maintenance. It can be fixed.


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