Arunkumar Khannur's Software Testing Knowledge Center
  1.9 Usability Testing or Evaluation

Co-discovery Learning

Co-discovery Learning (CL) is an adaptation of the most commonly used type of user testing - think aloud protocol (TA). In CL, users are grouped in pairs. It is preferable to pair two users who know each other into one group so that they won't feel uncomfortable working together. Then product under test (or a prototype of its interface) and a scenario of tasks to perform are provided to test users. Now, test users start to perform the tasks using the product, and talk aloud naturally to each other whilst working together to accomplish a common goal using the product. CL technique facilitates talk aloud among users who are grouped in pairs and there by erroneous assumptions about the system can be noted. This technique can be used in development stages: design, code, test, and deployment.

Co-discovery Learning is more realistic than a single user scenario, as people in work environments often work in teams. The users often find it easier and more natural to vocalize thoughts with a colleague present. The evaluators can also quantify the time taken for various tasks, the number of tasks competed correctly, the error frequency, numbers of times the users accessed the help system etc. From this they can make more qualitative judgments such as the success or lack of the entire system; system sub-components; help system; effort required to achieve a particular result; quality of interface. In summary, this technique helps to test effectiveness and satisfaction related issues. However efficiency related issues are not covered.

For Co-discovery Learning (CL) technique we require 1 usability expert, 1 camera operator and a minimum of 6 users who should be observed in the exercise.. Different Users will have different problems. The number of users must be even since pairs of users are observed.

In order to perform Co-discovery Learning, first step is to pair the test users into groups of two. It is preferable to pair two users who know each other into one group so that they won't feel uncomfortable working together. the test users shall be provided with the product to be tested (or a prototype) and a set of tasks to perform. Then test users perform the tasks using the product, and explain what they're thinking about while working with the product's interface. As the Co-discovery Learning (CL) technique progresses, test users shall be made to gradually move from simple tasks to more difficult ones. During the testing, test users can help each other in the same manner they would if they were working together to accomplish a common goal using the product. At the end, test users are asked by the expert to record their findings in an evaluation form or memory test. Also, experts evaluate, analyze videotapes and record their findings. Findings recorded are reviewed by designed and are incorporated into the prototype which is again retested.

Co-discovery Learning (CL) technique has certain limitations. This method is quite time intensive. Co-discovery Learning may not uncover all errors as users are doing only a subset of the full amount of tasks. Users may complete tasks in spite of problems or errors encountered either through persistence or learning. Some errors may be impossible to find by this method, such as poor window or navigation structure which is still usable but not optimum. User testing only uncovers symptoms of problems, not the cause – this must still be inferred by an expert. Using two people at a time means that it can be harder to find a large enough representative group to conduct the tests.

Khannur's Book
Arunkumar Khannur, Software Testing - Techniques and Applications, Published by Pearson Publications, 2011 (ISBN:978-81-317-5836-6; Pages:341 + xxii)
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