日本語
“I don’t really understand system development requirement definition.”
“I know it’s an important process, but I’m not sure how to proceed.”
“What’s the purpose of doing it in the first place?”
For those who have such doubts or concerns, we will explain system development requirement definition in an easy-to-understand manner.
We will also introduce the position of requirement definition in the overall system development process, why it is an important process, and how to calculate specific costs.
You will gain an understanding of how to proceed with requirement definition and the key points to keep in mind. If you want to learn requirement definition from the basics, please refer to this article.
Akira Shimazoe
CEO of Solashi Japan LLC. Engaged in the development and operation of internal systems at Suntory. Founded Yper Inc., serving as CTO and CPO, contributing to product launch and growth.
What is Requirement Definition in System Development?
Requirement definition is the process of identifying the necessary functions, performance, and security requirements of the system to be developed, and deciding what to implement.
It is carried out in the early stages of system development and is an essential step for obtaining the expected deliverables.
To first understand the basics of requirement definition, let’s take a look at the following key points.
- The position of requirement definition
- Contents of requirement definition
- Who creates the requirement definition document?
The Position of Requirement Definition
The following table summarizes the overall picture of system development when outsourcing, organized by flow stage.
| Development Phase | Overview | Responsible Party |
| 1. Planning | Plan the purpose and content of the system | Client Company |
| 2. Requirement Analysis | Collect and organize user demands | Client Company |
| 3. Requirement Definition | Identify requirements to realize the demands and create a requirement definition document | Client Company (Can be requested to development company) |
| 4. Design | Design the system based on the requirement definition | Development Company |
| 5. Implementation | Develop the system | Development Company |
| 6. Testing | Conduct tests to ensure quality | Client Company & Development Company |
| 7. Operation & Maintenance | After release, transition to operation and maintenance | Client Company or Development Company |
Requirement definition is conducted based on the contents of the planning and requirement analysis phases.
Since it is conducted at the early stage of development, in waterfall development where steps cannot be reversed, it greatly affects the later phases.
To avoid confusion or trouble during development, it is important to create an accurate requirement definition document.
Contents of Requirement Definition
The content defined in requirement definition can be broadly categorized into business perspective and system/software perspective.
- Business perspective... Definition of business requirements to solve problems and achieve development objectives
- System/software perspective... Definition of system architecture, functional/non-functional requirements to realize business requirements
We will explain business requirements and functional/non-functional requirements in detail later.
In addition to the above, requirement definition also includes decisions on organizational structure, budget, and schedule. In the end, a requirement definition document summarizing all of these is created.
Who Creates the Requirement Definition Document?
The requirement definition document is basically created by the client company. Having this document makes it easier to request development from a system development company.
However, there are cases where the client company does not have the know-how or skills to create the document. In such cases, it is also possible to outsource this task to the development company.
That said, even if you leave it to the development company, you should try to create as much as possible in-house and reflect your requirements as clearly as possible.
To avoid future problems, it is important not to completely delegate all work to the development company.
The Difference Between Requirement Definition and Requirement Analysis
Both requirement definition and requirement analysis are important processes conducted at the early stages of development. However, there are clear differences between them.
As mentioned earlier, requirement definition is the process of identifying what is needed to create and operate the system. On the other hand, requirement analysis is the process of identifying what is desired from the system.
In terms of order, requirement analysis is conducted first to gather and organize requests from users and stakeholders. Then, in the requirement definition phase, the necessary functions, performance, usability, and quality to achieve those demands are defined.
Why Requirement Definition Is Important
Requirement definition is considered one of the most important phases in the system development process. Here are the reasons why:
- Because it serves as the framework for the contract
- Because it helps gain a shared understanding throughout the project
Each of these points is explained below.
Because it serves as the framework for the contract
In contracts with system development companies, the requirements specification document created during the requirements definition phase is used as the basis for finalizing the contract details.
Specific items reflected in the contract include the development scope, features, and quality. In addition, the required timeline for development is also estimated based on the contents of the requirements definition.
This step facilitates consensus building between the client and the development company and plays an important role in progressing the system development smoothly.
The requirements definition acts as the framework for the contract and is a critical step directly linked to the success of the project.
Because it helps gain a shared understanding throughout the project
Another important reason for requirements definition is that it helps establish a shared understanding across the entire project team.
Unlike tangible products, systems are intangible services. Without a clear foundation, the client’s ideas and needs cannot be properly conveyed to the development company.
Therefore, by using requirements definition to build the foundation of system development, the envisioned system is shared with all stakeholders in the project.
In addition, by documenting the requirements in a requirements specification, misunderstandings between the client and the development company can be avoided, and the necessary information can be properly shared.
Costs Involved When Outsourcing Requirements Definition
The cost involved in outsourcing requirements definition is generally calculated using the following formula:
| Requirements Definition Cost = Labor Cost (unit price per person-month/day) × Number of Months/Days Required for the Work |
In reality, the actual number of working days may differ from the initial estimate. Therefore, it is often difficult to calculate a precise cost before the work begins, and only a rough estimate is usually available.
The higher the skill level of the assigned engineer, the higher the unit labor cost. Likewise, the more complex the system requirements, the more workdays are required, leading to increased overall costs.
How to Proceed with Requirements Definition for System Development
This section explains how to proceed with the requirements definition for system development. By understanding the overall process, you can define requirements effectively.
Clarify the Issues to Be Solved and the Purpose of Development
First, clarify the issues to be solved and the purpose of the system development.
Clearly define why the system is being developed and what problems it is intended to solve.
At the same time, share the overall direction the project aims to take with all stakeholders. This prevents the project from deviating significantly from its original purpose during development.
Depending on the development method, the contents may be adjusted or changed along the way. In such cases, the initially shared goals help in decision-making and reaching consensus.
Define Business Requirements
Business requirements refer to the clarification of the workflow that will be systematized.
Organize the detailed steps, rules, persons in charge, tasks, and data management involved in the business processes, and clarify the scope of systematization and the overall business flow.
Defining the business requirements helps visualize how the system will contribute to actual business operations.
Create the Overall System Architecture
Once the scope of systematization is determined, create the overall system architecture.
By proceeding with the definition of functional and non-functional requirements in the next stages, you can draw a more precise and streamlined overall system picture. Identify the system components and clarify their roles and relationships.
The components that make up a system are broadly categorized into the following four types:
- Hardware... Computers, servers, printers, etc.
- Software... OS, applications, programming languages, etc.
- Network... Internet, LAN, WAN, etc.
- Data... Programs, configuration files, etc.
If any system components are missing, they may be treated as out-of-scope in estimates, so care is needed. Particularly, a lack of hardware may result in significant extra expenses.
Be sure to check thoroughly that all system components are covered to avoid missing elements in the requirements definition.
Define Functional Requirements
Based on the business requirements, define the functional requirements. Functional requirements are the minimum necessary features that the developed system must have.
Examples of specific items include the following:
- System processing details
- Types of data
After defining the requirements, make sure to check whether there are any elements that are difficult to implement or lack business impact.
If improvements are identified, adjustments should be made to develop a better system. If resolving the issue in-house proves difficult, consider consulting the development company for possible alternatives.
Define Non-functional Requirements
Next, define the non-functional requirements. Non-functional requirements refer to items that are not covered by the functional requirements.
Specifically, these include items such as usability, scalability, security, and performance.
Since many secondary items are also included, incorporating all possible non-functional requirements may lead to a budget overrun.
It’s important to appropriately determine the scope of the non-functional requirements.
Establish the Organizational Structure
Based on the overall system structure, as well as the functional and non-functional requirements, determine the organizational setup.
From these system requirements, the estimated workload and required technical skills for development can be inferred. Decide during the requirements definition phase how many members to assign and what level of expertise each member should have.
It’s also helpful to determine who will serve as the point of contact and what communication methods will be used, as this will facilitate smoother progress in subsequent phases.
Create the Budget and Schedule
By following the above steps, you will gather the necessary components to estimate the budget and schedule.
Start by calculating the required man-hours and schedule based on the system requirements and organizational setup. Then, calculate the cost of hardware procurement and personnel costs associated with development to establish the budget.
At this stage, the schedule can be a rough draft outlining the major milestones. Once the requirements definition is finalized, refine the details along with the estimates.
Create the Requirements Definition Document
Finally, compile all the defined requirements into a "Requirements Definition Document." Ideally, this document should clearly explain the system development overview to any reader.
After setting the items from 1 to 7, write in-depth content for each and compile it into a single file or booklet.
The quality of the requirements definition document can greatly affect the success of the project. Aim to create it as accurately as possible.
Three Key Points for Advancing Requirements Definition
Lastly, here are three key points to keep in mind when advancing with requirements definition. These are essential for ensuring smooth system development and should be considered early in the requirements phase.
- Clearly define roles and responsibilities
- Avoid vague definitions
- Allow for a buffer in the schedule
We will now explain each point in more detail.
Clearly Define Roles and Responsibilities
In requirements definition, the client company and the development company need to decide their roles and proceed in cooperation.
If the client company defines the requirements in-house, details such as organizational structure, schedule, and budget should be coordinated with the development company.
Even when outsourcing the requirements definition to a development company, the client should clarify the challenges and development goals. Also, business requirements must be gathered based on input from the company's own users.
To ensure both the client and development company can fulfill their roles properly, make sure tasks and responsible personnel are clearly defined.
Avoid Ambiguous Definitions
Ambiguity in definitions can lead to trouble during development.
Requirements definition is a crucial process where the client company can directly participate before moving on to design and implementation. Make sure all your intentions are fully reflected.
If development begins with vague definitions, even highly skilled engineers may not be able to deliver the expected results or deliverables. Furthermore, the project's goals and direction may become unclear during development.
To avoid such situations, it is important to thoroughly align on any ambiguous items.
Proceed with a Schedule That Allows Flexibility
It is essential to build in enough flexibility in the schedule defined during the requirements definition. If you rush to release and set an unrealistic deadline, it may actually lead to delays or issues.
To keep everything on track, confirm the required work time and allocate an appropriate number of days.
Even after development begins, it’s important to frequently check progress and adjust or revise the schedule as needed.
For System Development Requirements Definition, Contact Solashi
This article has explained how to define requirements for system development. Here's a summary of the requirements definition process:
| 1. Clarify the issues to be solved and the development goals 2. Define business requirements 3. Design the overall system structure 4. Define functional requirements 5. Define non-functional requirements 6. Decide on the organizational structure 7. Create a budget and schedule 8. Create the requirements definition document |
While this process is followed to define requirements, if your company lacks the know-how, outsourcing may be necessary.
Since requirements definition is a critical early-stage process in development, it's important to work with a reliable development company.
If you want a successful requirements definition, leave it to Solashi Co., Ltd. We can provide high-quality system development while keeping costs under control.
Our team includes several Japanese PMs experienced in launching businesses and handling startup projects. Even if this is your first time outsourcing system development overseas, you can trust us with confidence.
We also have many engineers well-versed in cutting-edge technologies such as blockchain and AI, and we can support various fields, from BtoB to BtoC. If you're interested, feel free to contact Solashi Co., Ltd.
Akira Shimazoe
Representative of Solashi Japan LLC. Born in April 1989 in Fukuoka Prefecture. Graduated from the Graduate School of Information and Mathematical Sciences at Osaka Prefecture University. Joined Suntory System Technology Co., Ltd., an IT subsidiary of Suntory Holdings, in 2014. Broadly responsible for the development, operation, and implementation of vending machine delivery management, efficiency improvements, and sales management systems. Founded Yper Inc. in 2017, serving as CTO and CPO. Contributed to the launch and growth of the app-linked delivery bag "OKIPPA." Selected for Toyo Keizai's prestigious "Amazing Venture 100" and Forbes' "Forbes 30 Under 30 Asia 2019."
