Task Four: Standard Laboratory-Based Usability Testing

Task Four: Standard Laboratory Based Study
The critical role of a usability test is to make recommendations for design improvement by identifying areas where end users experience problems with a product. In usability testing, the aim is to produce results from real users interacting with the system or product. By watching users interact with the system you are able to have insight in to which part of the system cause participants to encounter problems. Usability testing is beneficial not only to users but most importantly to the business (product owner).
There are different ways of conducting usability testing one of which is a standard laboratory-based usability testing. The laboratory can either be static or portable. The testing is conducted

The developers must have decided before hand what it is that participants will be doing in the study. It is also important for all stakeholders in the study to know what the results will be used for to avoid deception.
Usability measures
Different usability measures are used when conducting usability testing.
Effectiveness: The success of a product is determined the degree to which it is able to successfully perform its intended goal. We can deduce that a product is effective if few errors are encountered, tasks are accomplished, and the completion rate is high. Efficiency: A system is said to efficient when the number of tasks taken to accomplish a task are few. If there are many steps even though the user is able to move from one step to another seamlessly, the system is deemed to be inefficient. Efficiency deals with the time taken to perform a given task.
Memorability: The best measures of a computer system is its ability to allow the user to memorize its features with ease. A well designed should make it easy for users to memorize it once they have learned it. Users should be able to remember different features of the system with aid of commands and

However, the number of a test participants is largely dependent on what the team seeks to accomplish. According to techsmith.com “the number of participants varies based on the type and purpose of the test” (2009, p4). Table 1 below shows the criteria for deciding the number of test participants.

Table 1: Recommended Number of Participants by Testing Technique (Tech Smith, 2009) Benchmark
Metrics Diagnostic
(Formative)
Evaluation Summative Testing
How many? 8-24 users 4-6 users 6-12+ users
Metrics and Measures Focus on metrics for time, failures, etc
Tests current process or product Less formal
Increased focus on qualitative data More formal
Metrics based on usability goals
Why Establish baseline metrics Find and fix problems Measure success of new design
When Before a design project begins or early in development During design At end of process
How often Once Iterative Once Source: Ginny Redish

Having taken into account these principles of laboratory based usability studies; one is likely to carry out a experiment without incurring a multitude of inaccuracy and at the same time they can perform a study that like all academic studies should, adds to the existing body of knowledge for the betterment of