Prototyping & Design LCN 18

Two Types of Design:

• Conceptual Design

• Physical Design

Prototyping

Well understood and used technique in engineering where novel products are tested by testing a model prototype.

Prototypes can be:

• Paper-based

• Software-based

Prototyping 2nd Definition

Limited representation of a design that allow users to interact with it and explore its suitability.

Prototyping allows Stakeholders to

• Interact with the envisioned product

• Gain some use experience

• Explore imagined uses.

Aim of prototyping is:

• Save time and money

• Have something that can be tested with real users

Traits of Prototyping

• Experimental and partial design

• Important element in UCD

• Involves users in testing design ideas

• Typically done very early in design process

• Can be used throughout SDLC

Examples of Prototypes:

• Series of screen sketches

• Storyboard

• PPT slideshow

• Video

• Lump of wood

• Cardboard mock-up

• Piece of software with limited functionality written in target language or any other language.

Why do we need prototypes?

Because in traditional software development, you cannot test a product until implementation, which can be very expensive and time & resource consuming. This results in design errors that may not be fixable due to the fact changes are far too expensive in this stage, leading to design errors being left in the product if not too bad. Think of Oblivion.

How to break the Implementation Paradox

1. Build a prototype of basic functionality

2. Test the prototype & uncover the design errors

3. Correct the design errors

4. Repeat until you reach a clean design

Prototyping is heavily used in ___

industry.

What do we prototype exactly?

• Workflows, task designs

• Screen layouts and information displays

• Difficult, controversial, critical areas

The Software Prototyping Trifecta

1. Customer feedback —→ used for 2

2. Develop/Refine prototype —→ uses 3

3. Testing of prototype by the customer —→ uses 1

Pitfalls of Prototyping

1. Need a good starting point

2. Need to understand what is wrong

Advantages of Prototyping

• Users can try the system and provide constructive feedback

• An operational prototype can be produced in weeks

• Users become more positive about implementing the system because they see a solution that will meet their needs

• Prototyping enables early detection of errors

Disadvantages of Prototyping

• Each iteration builds on the previous iteration and further refines the solution, makes it difficult to reject the previous solution and start over.

• Because prototyping focuses on pleasing the customer, formal reviews get skipped, so scope becomes hard to control.

• System documentation is often absent or incomplete since primary focus is on development of the prototype

• System backup & recovery, performance, and security issues can be overlooked.

Journey of the Prototyping Process

1. Goals

2. Functionality

3. Develop

4. Evaluate