Presentation on theme: "INPUT DESIGN Input Data Persistent Data Process Output."— Presentation transcript:
INPUT DESIGN Input Data Persistent Data Process Output
Why be concerned about INPUT DESIGN? Garbage In - Garbage Out (GIGO) Data Verification & Validation (V&V): Self-checking digits or check-digit Combination check Limit and Range checks Completeness checks
BATCH INPUT - ADVANTAGES Collecting and Entering can be done off-line. Entering data can be done by trained personnel. Processing can be done very quickly. Processing can be done during non-peak times.
BATCH INPUT - DISADVANTAGES Data collection usually has to be a centralized activity. Data entry usually needs to be done by specially trained personnel. The processing activity is delayed, hence the possibility exists for data to be considered old or untimely when it finally gets processed. Since processing is usually done during off-hours, input errors detected during processing would not get corrected until the next regularly scheduled processing of input data. The off-hours computer operator may have to call the systems analyst or programmer if the program malfunctions.
ON-LINE INPUT - ADVANTAGES The data can be entered by its owners. The data can be entered as close to their origination as possible. Immediate feedback can usually be given regarding the correctness and acceptability of the data. The input data can immediately update a database thus making it as current as possible.
ON-LINE INPUT - DISADVANTAGES Equipment may be more costly to perform the input. Users are not always well trained to input data. User data entry procedural controls may be lacking. Software must have additional controls to handle it. Data is often only entered during business hours thus impacting the normal computer load. The data entry activity could actually be slower than the equivalent batch processing for the same data.
GENERAL GUIDELINES FOR INPUTING DATA Input only necessary data Let the system calculate or derive data Use Business Codes where appropriate Movement should be left-to-right, then top-to-bottom
BUSINESS CODES Serial - based on arrival time Sequential - based on an ordered table Block - based on range of letters/numbers Alphabetic - based on an abbreviation or other convention Group - any combination of the above four
SERIAL BUSINESS CODES BANK Based on Arrival Time - “first come, first serve”
SEQUENTIAL BUSINESS CODES BANK Based on “meaningful organization” - sorted Bob Stan Sharon Carol This example: sort by first name, then assign a number
BLOCK BUSINESS CODES BANK Based on a range of letters and/or numbers Bank Customer Types Merchant/Business A E9999 Personal Checking F M9999 Personal Saving N T9999 Custodial U Z9999
ALPHABETIC BUSINESS CODES Based on an abbreviation or some other scheme STATES UNITS OF MEASURE AZ = Arizona CA = California MI = Michigan NY = New York etc.... GA = Gallon QT = Quart PI = Pint YD = Yard FT = Foot IN = Inch etc...
Example: Use of a Group Code in a Paint Store Product Class Base Color Base Type Unit of Measure Legend P = Paint S = Stain = Browns = Greens = Blues = Yellows = Reds 0 = None 1 = Lacquer 2 = Water 3 = Oil P = Pint Q = Quart G = Gallon Paint Product Examples: S G P QS P P G GROUP BUSINESS CODES
GRAPHICAL USER INTERFACE (GUI) DESIGN Pop-up menus Pull-down menus Drop-down/List boxes Option (Radio) Buttons Check Boxes Text Boxes Spinners Command (Push) Buttons Menu Bars Menu Pads Maximize/Minimize Button Bars Tool Bars Scroll Bars Docking Navigation Data Entry Modes of Operation: OBJECTSOBJECTS
Data Entry Form/Window With Navigation Choices Option (Radio) Buttons (choose one) Spinner Pop-Up Menu Command Buttons
The Prime Objectives Make the user's tasks easier to perform with the information system than without it – It should be intuitively obvious to the most casual user Design the interface to meet the user's needs – Adapt technology to the user instead of forcing the user to adapt to the technology Meet time and resource allocations – Get it out on time and under budget
GUI Design Considerations Icons are often intuitive Consistent use of icons is important Size of icons & text is important Number of icons - not too many Use of color - not too much
Five Basic Steps for User Interface Design 4 Get to know the users 4 Analyze user tasks and goals 4 Establish design and usability goals 4 Storyboard some design ideas 4 Evaluate the designs 4 Repeat as necessary
Design for the most common users and tasks – Design for 80% of users and tasks – Design for users, not engineers Establish usability metrics – Average time to perform a task – Maximum number of errors Establish Design and Usability Goals 1 of 3
Prioritize the Features Importance to the users or their tasks The most common actions must be addressed first Required time and resources Which features can wait – Bells and whistles – Future release plans 2 of 3
Costs of Not Making a Feature Usable Increased documentation costs Increased technical support costs Increased training requirements Maintaining backward compatibility $$$ Liability $$$ 3 of 3
Storyboard Some Ideas Construct usability prototypes – Low fidelity »Paper and pencil »Screen printouts – High fidelity »Visual basic »Hypercard 1 of 8
More than One Solution Exists Generate several designs and test them all When designers cannot agree, test the designs Document the designs and the reasoning behind them – This inhibits going back to an old design that has problems 2 of 8
Design References Use platform guidelines – IBM CUA (Common User Access) – Windows Style Guide – Mac Human Interface Guidelines User Interface Design Books – The Design of Everyday Things by Donald Norman – Usability Engineering by Jacob Nielsen – Practical Guide to Usability Testing by Janice Redish and Joe Dumas – About Face: The Essentials of User Interface Design by Alan Cooper 3 of 8
Exploit User Intuitions and Expectations Left to right & top to bottom Obvious actions should be default actions Speak the user's language – Use terminology that users use Capture user metaphors – Word processor = typewriter 4 of 8
Remain Consistent ENTER is progressive ESC is regressive Avoid custom controls – If it behaves the same, it should look the same – If it behaves differently, it should look different 5 of 8
Make Information Visible Human memory is fallible – Interfaces that rely on human memory are prone to error Provide the information users need when they need it Suggest formats with examples Provide immediate feedback 6 of 8
Provide Obvious Error Control Prevent errors – Limit the effect the user has on the system – Confirm all destructive actions Make errors recognizable as soon as they occur – People believe that what they see is a result of their last action Allow immediate error recovery 7 of 8
Careful with Colors Use colors consistently – If red is a danger color, don't use it as part of the non-functional aesthetic fluff Never use more than 7 colors – No more than 5 is better 8 of 8
USABILITY CONSIDERATIONS* (User-Centered Design) 4Field studies to observe potential users to determine needs 4Behavioral designers devise conceptual models and ensure that the model works through-out a complete task cycle rather than merely supporting isolated tasks 4Prototypers create testable models 4User-testers place models in users’ hands and report what works and what doesn’t 4Graphical and industrial designers make products attractive to use and affordable to build 4Technical writers, however good tools communicate their own functionality * Excerpt from: Norman, D.A., The Invisible Computer, MIT Press, as presented in: Coffee, Peter, “When ‘Good Enough’ Is All the Market Needs”, PC Week, September 7, 1998, page 43.