G063 - Human Computer Interface Design Designing the User Interface

G063 Learning Objectives:

At the end of this topic you should be able to: discuss the factors which affect the design of a human–computer interface

Synoptic Learning Objectives: At the end of this topic you should be able to: describe the design considerations for data-entry screens; describe how data-entry screens can be tailored using form controls explain the advantages and disadvantages of tailoring a user interface;

Data-entry screen

Tailored user interfaces Advantages: simplified user data-entry –less mistakes made by novice users faster to enter data & make choices –user is more productive data-entry can be validated –less incorrect data stored Disadvantages: level of knowledge required to create & test the interface time taken to modify the interface simplified interface may restrict advanced users

Colour follow corporate colours colours shouldn’t clash (complementary) draw attention –e.g. highlight mandatory fields in a different colour used to code information: –debit in red, credit in green –must match users expectations must consider colour blindness!

Layout consistent layout –follow house style –same order as source documents information flows logically on-screen –top to bottom & left to right –similar items grouped together buttons in the same place on each screen –including clearly marked exits uncluttered –good use of empty space (white space) –only include relevant information (concise & not excessive)

Consistency design follows corporate image –follows existing house style layout on screen matches layout of source documents –or the order in which the operator receives the data logical order and flow of data entry for the user –data entered in the correct expected places consistently placed prompts to identify data entry area design of buttons should aid transition appropriate level of language & terminology used throughout –so user can interpret requests appropriately

Quantity of Information Aim: ensure users can effectively use the interface –can complete tasks quickly & accurately a cluttered interface will confuse the user –make good use of empty space (white space) too much information will slow the user down –only include relevant information –concise & not excessive

Font size & style text used should be in an easy to read size –size appropriate to the on-screen interface  if font size is too small, information may be illegible font style must be clear so words easy to read –serif and sans serif fonts should be used for legibility –decorative fonts should be avoided as they lack clarity consistent use of font size style throughout no dramatic variations in font size and style –may lose the consistent look and feel of the system –use of familiar fonts will enhance the ease of use

Complexity of language appropriate level of language & terminology used –consider age & experience of users –so user can interpret requests appropriately error messages should be clear and useful –use simple and natural language prompts use familiar and relevant terms –OK, Cancel …..

Form Controls Combo Box Option Button (radio button) Check Box List Box Spinner Text Box Label Button

Form Controls Combo Box –available options are selected from a drop down list Option Button –choice selected by the user from a group of options/values Check Box –options can be selected List Box –the user can select one or more items from the given list

Form Controls Spinner –to increase or decrease values Text Box –text is entered and then used in the application Label –instructions given to the user Button –the user pushes a button to start an event –buttons can be linked to macros

Methods of Dialogue Main features: prompts nature of input methods of input feedback The type of dialogue will depend on: the style of user interface being used the tasks to be completed

Feedback used to support correct data entry –by providing useful assistance notify user if data entered unsuccessfully –and/or successfully ( ) error messages should be clear and useful –use simple and natural language utilise audible and visual cues –beep for incorrect entry –use colour to highlight incorrect entry

Prompts used to support correct data entry –by providing useful assistance notify user if data entered unsuccessfully –and/or successfully ( ) error messages should be clear and useful –use simple and natural language utilise audible and visual cues –beep for incorrect entry –use colour to highlight incorrect entry