The underlying principle of this course is that success in IT industry (and in many other areas of business and life) relies on good planning. In particular we use the acronym DDE which stands for Design - Develop - Evaluate. This is a simplified version of the Systems Development Life Cycle (SDLC) which is a framework for developing of modifying information systems.This framework can be used across a wide range of activities, including those outside the software development area. The SDLC usually refers to a 5-step process and is used in the Software Development industry, but we cut this to a 3-step model which was developed for designing instructional material.

How do they relate to each other?

DDE Model
SDLC Model


The Design phase involves a sound analysis of the needs of the task. This usually involves collecting sufficient information to understand the client and their needs and may include a Design Brief for the task. Design can be thought of as Identify - Specify - Plan
  • Identify the needs of your client or your task - what are you trying to achieve? What are your objectives? Are they achievable?
    Can they be measured? Is there sufficient time to produce the required product?
  • Specify how you are going to achieve this. What resources will you need? What constraints or obstacles might you encounter? At this stage you might establish a simple Gantt Chart.
  • Plan your method of attack. Decide how you will use your resources to overcome constraints and reach your goals. This is the stage where you will set out details so your Gantt Chart will become more detailed, specifying times and sequences for the sub-tasks.

The Development phase is applying the details determined in the design phase (Develop) and performing testing (at least Alpha Test). As you build your product you will be performing alpha testing. You should record any changes that require modifications to your plan. This may require modifications to your Gantt Chart. You should keep a record of all significant changes as this provides evidence of iterative development.

The Evaluation phase determines how well we met the requirements and what factors contributed. You need to go back to your first stage to see what you were trying to do, then evaluate how well it was achieved. This will probably include feedback from your client or supervisor. We use four criteria for evaluation - Context (the environmental influences on the process) - Inputs (the resources used including hardware and software) - Process (the actual production of the result) and Product (how well does the product meet its objectives). You will be expected to evaluate based on this CIPP approach.

This page provides some useful DDE links
  • The SDLC system is often used in software development. The SDLC can be expanded into 9 steps. Identify how they relate to your DDE cycle. There is probably only one of these 9 steps that is not DDE. Which one is it?


The DDE Cycle - part 1
In the early years of development of computer programs, programmers and their managers learnt some painful lessons about software development. Many software projects were over budget, late, full of bugs and failed to live up to expectations.
Several models have been developed for managing software development. Many of these incorporate the Design-Develop-Evaluate model (DDE).
After starting with a definition of the problem, coupled to a feasibility study, production proceeds through a cycle consisting of Design, Develop, Evaluate, until the project is finished and Implemented.

Figure 1
Figure 1

A feasibility study is often used to broadly define possibilities, without being overly specific. The feasibility study can establish some development boundaries, eg. set guidelines for how long a user must wait for a response (the response time) from a system.
The following points outline various aspects of the feasibility study, some of which are relevant to our situation

  • Find out what else has been done!!!
  • Consider the intended audience
  • Decide which hardware will be used
  • Choose the software to develop with
  • Consider the infrastructure requirements of development
  • Think about how the program will be delivered
  • Investigate how the program will be installed
  • Make an estimate of how much the development will cost
(Rob Phillips Curtin University of Technology)
After the initial design is produced, there is a focus on developing the requirements specification in finer and finer detail.
With each pass through the design process, there should be fewer and fewer changes to the design, until it is eventually complete. It is then appropriate to sign off the design, after which it cannot be changed.

Development cycle
Once it has been decided that a project is feasible and funding has been obtained, development can start. Development occurs in the cycle shown in Fig. 1, that is design, develop, evaluate.
In the introduction we made the point that it was essential to separate the Design Process from the Production Process, as shown in Fig. 2. It cannot be emphasised enough how important it is to design the project as comprehensively as possible on paper, in order to produce a quality project within budget
The signing off procedure is an important incentive to ensure that the design is complete, and that members of the team will not attempt to change some components of the design at a later stage.
After the design has been completed, the Production Process (Development) commences. Some aspects of production may have already been completed. The user testing starts another pass through the development cycle.
Figure 2
Figure 2

The key points made in this paper to efficiently produce educationally effective IMM materials are shown below:
  • Separate design from production
  • Design the project as comprehensively as possible on paper through a
    • thorough Requirements Specification
    • comprehensive storyboard/plan
  • Use prototypes where appropriate
  • Document all aspects of the development