Understanding the importance of documentation 

Documentation, in simple words, means any written material, with or without supporting illustrations. It is used to list, explain, and guide the reader through certain features of a product, a process, a smaller part of a bigger system, or literally anything worthy of taking notes about. It helps with easier visualization and helps us understand the problem(s) at hand since all the important points are recorded.

In terms of the software industry, documentation plays a crucial role right from the start of the project, and this continues even after the software is released. It doesn't matter whether it is a small project or a big enterprise-level product. It may be created by a small team of developers, or by a big, multi-vendor distributed team across the globe.

In all these cases, we require some form of written, documented material, starting with requirement specifications, solution designs, the flow of information, and more. This makes software development and its intended use easier in the different phases. Documentation is needed to describe the various functionalities of the software so that we can collect and collate all the product-related information at a single point. This makes it easier for the different stakeholders involved, such as business management, product owners, developers, testers, and so on, to discuss and share all the major questions that may arise during the entire life cycle.

There are many reasons why documentation is essential. The main arguments that will be made here surround development and process documentation but can also be applied to other contexts. The following subsections highlight some of the reasons why you should pay more attention to documentation.

Clear definition of requirements and scope

Imagine you are building the house of your dreams without any blueprints or initial specifications. Without these, you don't know the plan of the house or what the size of the rooms will be. The instructions that go to the building crew arrive on an ad hoc basis. The building crew might be rotating their shifts, which means questions will be asked at random times. In the end, do you think the house will end up looking like your vision?

A similar thing happens in software development if we don't have clear and concise documents establishing the business goals and requirements. Even though the requirements might not be finished before development starts, as in the preceding example, the work with requirements that goes on during the development cycle needs to be reflected in the documentation. If there is no documentation, then the developers may go astray from the core functionality that the product is expected to deliver during the development life cycle. Having this aspect documented ensures that all the different stakeholders involved are moving toward achieving the same goal. And if anyone forgets what was discussed or if someone new arrives in the team, they can always go back to the documented material for reference and validation.

The importance of clear definition and scope applies as much to agile development processes as they do in traditional development processes. When using agile, there are still requirements that should be documented. If we look at Scrum, the most widespread agile process, as an example, we have requirements documented in a backlog, with more detailed requirements the closer they are to being worked upon. We have a scope defined in work chunks called sprint plans, again with more details in the upcoming sprint compared to sprints down the line. Not all this might be documented in traditional documents, but it is still documentation, be it post-it notes on a wall or a backlog in a web-based requirement tool.

Assisting in testing and maintenance

Let's once again use the example of your dream house. Once it has been built, documentation would be used to verify the various aspects of the house, that it looks and functions in the same manner as you intended it to. We might need the blueprint, based on which we can say whether all the specifications have been met. If something is not operating properly, we can compare it against the blueprint, identify the flaw, and ask the builder to rectify the problem. A few years down the line, when a pipe breaks in the bathroom, the contractor who was hired to fix the issue can look at the blueprint to know in which walls the pipes can be found in.

Similarly, once the development phase is complete and the product has gone through a testing phase, the tester will need to know what to expect of the system. The tester will then prepare the test plans accordingly. In the same manner, once the software has gone into production, the support team needs to know how the system should behave under different use cases. So, by comparing it with the expected behavior, they can identify potential bugs quickly. This example has shown that documentation plays a major role, even after the release.

Better collaboration and teamwork

Creating software is a team effort. As such, when you pass tasks between different team members, it is vital to have a common view of the work to be done. Different members might have different ideas on how to implement different functionalities and what to implement, but everybody needs to understand the same requirements and processes to share a common view of what needs to be accomplished, and how it should be done. Getting everyone to understand the common goal is where documentation helps.

Two developers can share a design specification of a system by using an API between two components. One developer could implement the API, while the other developer could start implementing code for consuming the API. This parallel work requires a common view of the details in the API, from its general functionality all the way to the details of the method names in the API. A developer can read/write a design specification, describing how a system/module should work, and then a tester can read the same design specification when creating a suite of tests for that system/module. This is a good way of collaborating, given that you have good documentation that is being adhered to.

In today's world, where the whole team is distributed across different parts of the world, there is a high possibility that different members with different backgrounds can interpret information differently. Having a central piece of a written document that can be referred to when solving a major issue can minimize confusion and ambiguity. This documentation assists in better collaboration.

Increases the team's competencies

You must have heard of the phrase, "Don't put all your eggs in the same basket." Well, why do they say that? It is quite simple. Imagine you are super hungry and are dreaming of a perfectly cooked egg for breakfast. If all the eggs are in just one basket, if the basket were to be dropped and the eggs smashed, you would be left with nothing but an empty stomach. What you need to do is distribute the eggs so that even if one basket falls, you still have enough eggs to enjoy your breakfast.

This is similar in the case of the software development world, which brings us to the next reason why documentation is important: it is not efficient for just one person to have all the knowledge that is required. If that person is not available for any reason, then the work slows down or stops while the team is trying to figure out the problem. However, if that knowledge was documented, then the progress of figuring out a solution to a problem is usually much quicker than reverse engineering or guessing.

Preserve good procedures in the organizational memory

When we have well-written documentation for a successful project, it serves as a reservoir of all the good processes and decisions that contributed to our success, which can then be derived from and applied to a new project. It also throws light on what didn't work and where improvements can be made; this can help in cutting down the development time for the new project as you have a template of what works and what doesn't work. Everyone loves to succeed and apply what they've learned to their next project, and effective documentation helps in facilitating this.

For example, consider that your organization has finished a project on time and within budget for an important client. During the project, a special planning method was used, and several risks were identified and handled. In the project documentation, the risks, their mitigations, and their special planning procedures were covered. Later, another client comes along with a similar project, but unfortunately, the project team that handled the successful project is not available. Here, the documentation from the successful project can be used as a starting point for the new project; the special planning procedures can then be used during the project planning phase and the risk documentation can be used as input for the risk planning phase. Thanks to good documentation, the new project has a much higher chance of success than it would have had otherwise.

Documentation is important when working with agile development processes

Many people utilizing agile development have the misconception that you don't need any documentation while doing agile development. We would say that you need documentation in agile development as much as in any other paradigm. You do need to be smart about how you write your documentation, though. The agile manifesto states that there should be a focus on working software over comprehensive documentation. However, you could argue that good documentation helps to create working software, so this is completely in line with the agile manifesto.

Before we move on to the next section, let's quickly recap what you have learned so far. In this section, we have learned what documentation is, as well as its importance. We learned how crucial documentation can be, particularly in the software industry, from the inception of the product to after its release. This promotes better collaboration and teamwork among team members and helps in resolving dependencies on one individual. With good documentation available for previous projects, it becomes easier to understand what works and what doesn't, and you can get a good head start with new, upcoming projects. At this point, you are aware of why documentation plays an important part in the entire software life cycle. In the next section, we will go a bit deeper and understand the subtle differences between good documentation and bad documentation. We will also discuss how to achieve efficient documentation.