Usability Inspection n Usability inspection is a generic name for a set of methods based on having evaluators inspect or examine usability-related issues. n It is intended as a way of evaluating user- interface designs. n Usability inspectors can be usability specialists, but can also be software development consultants with special expertise, end-users with content knowledge etc.

Four ways of evaluating user interface n Automatically- by running a user interface specification through evaluation software n Empirically- by testing interface with real users n Formally- using exact models and formulas to calculate usability measures n Informally- based on thumb rule, general skills and experience. Usability inspection falls here

Usability Objectives n It is aimed at finding usability problems in an existing user-interface design and then using these problems to make recommendations for fixing the problem and improving usability of the design. n Usability refers to how easy it is for the users to learn the system, how efficiently they can use it, once they have learned it and how pleasant it is to use.

Use of inspection problem reports n Fixes and other redesign suggestions must be generated. n Effective use of a list of usability problems requires that these problems be prioritized with respect to the severity n It is also necessary to get an estimate of the software cost associated with implementing the suggested redesigns

Team building and Education n Another objective of usability inspection methods can be communication of information to members in the group n Also, instructors can use usability inspection to provide rapid training of students in user interface design classes

Inspection methods n Heuristic Evaluation n Guideline reviews n Pluralistic walkthroughs n Consistency inspections n Standard inspections n Cognitive walkthrough n Formal usability inspections n Feature inspections

Inspection methodology issues n Inspection Framework- how does a usability inspection participant actually evaluate an interface. Deciding what guidelines to use is really about deciding what usability inspection method to choose. n Scenarios- should inspectors evaluate in terms of specific end user tasks or interact with interface in more general and open ended instructions n Inspector experience-leads to more effective usability inspection problem reporting

Methodology issues (contd) n Individual or Group Inspection- Individual inspections ensures that inspectors are not influenced by other opinions. But in teams, people can reinforce each other, helping each other to notice problems that might not have been seen individually.Both can also be carried out indifferent phases. However time is a tradeoff for having both inspections. n Usability of methods- learnability and usability of inspection method. Effort to learn a method could trade off with effectiveness in producing results

Validity of inspection results n How predictive are the problems of the end- user problem? n We want to know how seriously to take the problem w.r.t making recommendations for modifying the software. n Identifying severe problem is especially important n failure of inspection problem reports to predict end user problems n account for problem predictions that do not correspond to end user problem- false positives

When to use inspection methods n Inspection methods are not suited for use in the very early phase of usability engineering lifecycle where no interface design has been designed or implemented n Also, it is poorly suited for use very late in the cycle, when the system has been released to the customers. n Interface design must at least exist. Implementation is not required

Cost benefit analysis n What inspection method to use decisions are trade-offs about time and resources. n Heuristic evaluation has the discount usability perspective whereas cognitive walkthroughs are more formal and expensive.

Using video in the BNR usability Lab n Users were video-taped as they test- drive the product. n Focus was user-interface testing. Identify user interface problems, recommend improvements to the interface and re-test the modified interface. n Video was the main method of data collection

Goals of usability lab n To identify all potential problems rather than waiting for the product to be released. n Communicate the results to the interface designers and convince them. Developers are most easily convinced if they see the users interact with the product. Thus, video becomes an essential communication tool.

Co-Discovery Learning n Videotape two users as they work together and discover how they use the product by trying it out. Usually no user-guide is provided. n Conversation between two users makes it much easier to pinpoint usability problems. Testing without a user-guide is realistic as many users do not read a guide. n However we need to prioritize usability problems, and for this detailed analysis of video tapes needs to be done in order to obtain a quantitative measures of usability.

n Quantitative measures are used to compare the usability of the product with that of the competitors. n Instead of viewing usability test as a way to reveal negative aspects of the interface, designers realize that it can show how well their interfaces compare to the others. n Disadvantage of video segments - considerable time is required for detailed analysis and to pick out relevant segments. n To speed up a U-test was designed which automated the analysis and enabled doing much work in real time