1. Ergonomics

Ergonomics

  • Ergonomic issues regarding software design: 
    • effectiveness of screen design
    • ease of use
    • appropriate messages to the user 
    • consistency of the user interface


Ergonomics

Ergonomics is the study of the relationship between human workers and their work environment.

Poor ergonomics in the workplace reduces workers productivity and can cause health issues. The most common and most debilitating computer-usage health issue is Repetitive Strain Injury (RSI). Other health issues involve general muscle strain and vision problems. Ergonomics for computer users includes the design and placement of equipment together with procedures to prevent and minimise injuries.

Ergonomic Issues Regarding Software Design

Software design from the user’s perspective is very much about the user interface. 

  • For many users, the user interface is the system. 
  • Software developers must create products that meet the needs of users. 
  • Products that provide fantastic functionality but have poor user interfaces will not be used. 
  • The user interface is the most important aspect of most software products. 
  • The better your user interface the more people will use your product.

In terms of ergonomics, the users’ experience should be an intuitive one. 
  • Effective user interfaces allow software products to be used with minimal training. 
  • The user is able to infer the underlying processing from clues inherent in the user interface. 
  • This is a clear indicator of a truly user-friendly product. 
  • How is this achieved?
Design Tips For Effective and Intuitive User Interface
  1. Consistency
    1. The most important aspect of user interfaces is consistency. 
    2. Vital Points to consider are:
      1. Set standards and stick to them
        1. Based on industry standards and specific for your app
      2. Explain the rules.
        1. Develop a simple set of rules that apply to entire app
        2. You only need to explain it once then.
      3. Use Interface elements correctly.
        1. Know when and how to use screen elements. e.g. command buttons, check boxes, radio buttons, list boxes, menus...etc.
        2. Never although standard operation of screen elements to perform unexpected functions.
      4. Use Colour appropriately
        1. Use colour sparingly
        2. Don't override system settings - the user chose them
        3. Maintain sufficient contrast between text and background
      5. Use Fonts appropriately
        1. Fancy fonts decrease readability
        2. Use fonts that are easy to read
        3. Don't override system fonts
        4. More than 3 fonts on a single screen is too much
        5. Use fonts consistently
        6. Have a reason for font change - incl size, colour, typeface, style or colour.
      6. Alignment of data entry elements.
        1. Text boxes and their labels - left justified
        2. For data
          1. Integer - right justify
          2. Floats - align on decimal point
          3. Text - left justify
      7. Provide consistent methods of reversing actions.
        1. Provide Undo functions
        2. Provide confirmation before major changes to data.
  2. Appropriate Messages to the User
    1. Messages to users are the primary method applications use to communicate problems to users. 
    2. If these messages are poorly worded then users will perceive the product poorly. 
    3. Messages should imply that the user is in control not the software. 
    4. Use full words and sentences, not abbreviations and codes. 
    5. Ensure messages are unambiguous and are positive. 
      1. They should provide insight as to how to respond to the message.
      2. The wording of messages should be consistent across the application.
    6. The placement of messages should also be consistent. 
      1. Generally, users expect messages to appear in the centre of the screen.
    7. Many messages are the result of an error of some sort occurring. 
      1. It is usual to provide some visual clue as to the severity of the error.
    8. Many messages require a response from the user e.g. Yes, No or Cancel. 
      1. Many users will inadvertently hit the Return/Enter key. 
      2. It is important that the default option will not cause some potentially destructive action such as deleting or saving.
  3. Ease of use
      1. Good user interfaces are easy to use. 
        1. Screen elements that are logically connected should be grouped together. 
        2. Similarly, unrelated items should be separated. 
        3. White space or frames can be used to accomplish this task.
      2. Navigation between screens should follow the natural flow of the task. 
        1. Applications should be flexible in this regard; the user should be able to complete tasks in the order they require. 
        2. Software that forces a linear sequence for completion of tasks controls the user. 
        3. The user should feel they are in control of the computer. 
      3. Within each screen, information should be organised left to right and top to bottom. 
        1. In western society, we expect information to be arranged in this manner.
      4. Applications should support both novice and experienced users. 
        1. The provision of shortcut keys and advanced functionality should be available. 
        2. Functionality should not be hidden from the user, as this is how most users learn, by exploring the interface.
      5. Some applications remove menu items that are currently not available; in most cases this is poor design. 
        1. Rather than removing items, they should be greyed out and disabled. 
        2. In this way, users can see what is both available and unavailable, helping them to build up a picture of the entire application. 
        3. It is also poor practice to leave items active that are not relevant at the time. 
        4. In general, if selecting a command will just result in an error message, then that command should be disabled and greyed.
      6. Busy screens result in confusion for users. 
        1. Easy to use screens will have white space on approximately 50% of the screen. 
        2. Some applications go ‘icon crazy’. 
        3. Icons are great if the meaning of the icon is immediately obvious. 
        4. If the icon is somewhat obscure then don’t use it, use text instead. 
        5. Always keep screens simple.
    1. Acceptable response time in software 
      1. The time taken for a process to complete is known as the response time. 
        1. In relation to ergonomics, response time is the time taken for software to respond to some input from the user.  
        2. Users expect to see something happening because of their inputs. 
        3. If a process is likely to take longer than a second to complete then some visual feedback is required. 
        4. For example, in Outlook Express a progress bar is displayed to provide feedback to users as mail is sent and received (see Fig 1.25). 
      2. Response times of around 0.1 second are preferable to give users the impression of instantaneous response. 
        1. If response times are closer to 1 second or greater then users will feel the computer has taken control. 
        2. Response times that blow out to more than a few seconds will cause users to act and perhaps reboot or cancel operations. 
        3. Often response times are linked to the power of the particular machine or the speed of the network connection on which the software is installed. 
        4. Programmers should ensure users will receive adequate feedback regardless of the machine they are using.
      3. Software accessed via communication links, and in particular the Internet, is particularly vulnerable to response-time problems. 
        1. The speed of the communication link is beyond the control of the software developers. 
        2. In these cases, it is vital that developers include methods to ensure their products perform satisfactorily under the most adverse conditions. 
        3. For example, web-based applications should display appropriate messages in place of video and graphics whilst these items are loading. 
        4. In this way users can commence reading the content of the website whilst media items continue to load. 
        5. When downloading files, an indication of the approximate time the download will take provides essential feedback for users. 
      4. Input screens that contain many list and combination boxes provide excellent data validation, however the response times can often be less than desirable. 
        1. Data intensive applications will often require extra data structures to negate the need to perform real time processing. 
        2. For example, bank account transactions are not processed until late at night when processing resources are available; during the day, a record of the currently available balance is maintained. 
        3. Often a compromise must be reached between response times and data validation.

    Student Activity

    Using the provided document, produce a Summary of Ergonomic Issues associated with Software Design.


    Other information




    Comments