By definition, a system is "a combination of related parts organized into a complex whole." According to BusinessDictionary.com, a systems approach is:
"Management thinking that emphasizes the interdependence and interactive nature of elements within and external to an organization."
According to O'Brien and Marakas (Management Information Systems, 8th edition), a systems approach is:
"A systematic process of problem solving that defines problems and opportunities in a systems context. Data are gathered describing the problem or opportunity, and alternative solutions are identified and evaluated. Then the best solution is selected and implemented, and its success evaluated."
O'Brien and Marakas continue by defining systems thinking as the process of:
"Recognizing systems, subsystems, components of systems, and system interrelationships in a situation. Also known as a systems context or a systemic view of a situation."
Systems approach and systems thinking play important roles in systems analysis and design.
Systems Approach to Analysis and Design
Based on these definitions, a system approach for analysis and design, whether it be a website or a content management system or an application/tool, requires you to consider the dependencies and interactions of all the parts of the system.
Performing an Analysis using a Systems Approach
Core Components
The first step is to recognize that systems include technology and human components. The technology component includes items such as hardware, software, firmware, and digital connectivity. The human component includes items such as:
- content a human creates
- business practices, processes, and policies
- activities perform by a human
The human component should drive the technology component. There are times when the limitations and/or cost of technology requires the human component to adjust. Adjustments should not reinvent content, practices, processes, policies, and activities if usability is to be maintained.
User-Centered
The process of systems analysis and design should focus on the human or user perspective. The objectives are to:
- Identify what the user does as well as how, when, and why.
- Map the data, tools, controls, and output to the how, when, and why.
Tools and Techniques
Personas: You can start with creating personas. "Personas are fictitious characters created to represent the different user types within a targeted demographic that might use a site or product. Personas are useful in considering the goals, desires, and limitations of the users in order to help to guide decisions about a product, such as features, interactions, and visual design.[2]" In order to create personas for your system, review the first two parts of the series on creating effective personas (part 1 and part 2). With a set of personas, you can proceed to identifying tasks performed by the personas.
IDEF: Once you have the tasks, you can collect information about the task by using the IDEF (Integrated Definitions Methods). 
IDEF allows us to consider both the technology and human components together as to ensure the connections between the technology and human components are appropriate. All tasks have input that is used to create an output. Tasks are constrained by varies levels of controls that work to ensure the task is performed as designed. Mechanisms are the tools or aids required during the execution of the task.
Concept Mapping: Another way to collect and relate the parts of a systems is by creating a Concept Map. "A concept map is a way of representing relations between ideas, images or words. In a concept map, each word or phrase is connected to another and linked back to the original idea, word or phrase. Concept maps are a way to develop logical thinking and study skills, by revealing connections and helping students see how individual ideas form a larger whole.[1]"
Designing the Technology Component using a Systems Approach
One way to accomplish this is to take the series of interconnected tasks and identify how the mechanisms for each task are related. Using the IDEF again, create a series of connected technology tasks (or system functions). Input will focus on the data and its source. The controls will consider the constraints of the technology as well as any required rules that need to be included. The mechanisms are the components of the function. The output is the product or interface required by the user. This technique can be used to drill down to the code and data level.
The concept map and IDEF are good starting points for using traditional software design techniques and tools.
Conclusion
No matter what approach you use, remember that the systems approach to analysis and design is focused on identifying the components of a system and how they relate.
References
BusinessDictionary.comO'Brien and Marakas
IDEF Overview
Wikipedia: Concept Map
[1] CONCEPT MAPPING FUELS. Accessed 24 Nov 2008.
Wikipedia: Software Design [2] Wikipedia: Personas
