Iterative design with CogTool

CogTool is a tool helps to evaluate the effectiveness and usability of a interface. It basically predicts the time for a interaction task through an interaction path created by the user. Providing the evaluation of a interaction workflow in a logical way.

I’m not sure about the algorithm of CogTool, but sounds very interesting.

The developer of CogTool also provided a series of video tutorials Here.


An short example showing the usage of CogTool:

Implementation interface: Google Hangout chatting interface on mobile

Task: send an image to a friend on the chatting interface. The image is already in the mobile, not to take a new photo.

Figure 1 shows the design of CogTool for the original interface, which takes three steps.

The prediction of the original task is 3.6 s, as shown in Figure 2.


Figure 1


Figure 2

Figure 3 shows the design from CogTool for the re-designed interface, which takes two steps.

In the new design, I combined the first two interfaces by adding some buttons in the first interface, task is shown in Figure 3. The prediction of the new design is 3.1 s, which is faster than the original one, see the details in Figure 4.

In my opinion, the original design takes too many steps, and each step takes time for consideration. The “attach” icon on the chatting interface doesn’t have a clear representation for “send a photo”, the “take photo” and “Attach photo” item on the second interface also takes time for thinking.

The original design and re-designed image is shown in figure 5.


Figure 3


Figure 4


Figure 5


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