By Aaron Tan Dani

In past articles we’ve looked what Enterprise Architecture is, who needs it, why it’s necessary and when to do it. In this article, we’ll look at where to start. But before we do so, it’s important to do a brief recap of EA just so everyone is clear what we are talking about.

Traditionally, Enterprise Architecture has been used to document the design of an organization – from its operations and business process to its systems and IT – and then to use that information to reduce complexity, increase collaboration and improve productivity.

Today, due to the advent of the Internet and digitization, Enterprise Architecture is increasingly seen as a way to keep an organization agile and nimble, so it can respond to changes and disruption. It is expected to spur innovation so that organizations to achieve their desired vision in this ever competitive market.

A natural question for any organization that is new to Enterprise Architecture is “where to start?” In EA there are two core approaches: top-down and bottom-up. Each has its pros and cons. It should be mentioned that the former deals with “to-be” situations while the latter deals with “as-is”. 

Top-down approach
In most cases, Enterprise Architecture involves a top-down approach, starting with the organization’s overarching or grand strategy and funnelling all the way down to implementation. In other words, the top-down approach starts with general models and proceeds with models that are increasingly detailed until a complete definition of the solution is achieved.

A top-down approach focuses on the strategic planning aspect of EA. You could say it’s an  analytical or even theoretical approach. But it is one that allows you to cover the entire breadth of the business and the IT systems that supports it. You will have a clear view of where every component fits in, in a seamless way.

By adopting a top-down approach, an organization is able to devise a structure that is very collaborative and efficient all the way down the line. EA architects are able to create very coherent solutions for specific business requirements using this approach. It also makes it easier for the financial department to assign IT budgets with EA initiatives when it is done like this.

There are downsides too. One potential issue is that a top-down approach, which by definition deals with “to-be” situations, may be too general or even theoretical and thus might not be as practical or feasible for what the situation really is. In other words, there is a possibility of it being disconnected with reality on the ground.

Another potential drawback is that because this approach calls for the strategy to be drawn up and passed down to the various domain architects, it might hinder the creativity of these architects.

The top-down approach, also because of its very nature, takes more time to implement as there is a need to achieve consensus around a common “to-be” vision for the company. Organizations that can afford to wait longer to see the tangible results of Enterprise Architecture can adopt this approach. It will offer those organizations to achieve their big picture ambitions.

Bottom-up approach
As its name suggests, this approach starts from the bottom where architects focus on a specific part of a problem and provide a proposed solution to solve it. In other words, this approach looks at the operational aspect of Enterprise Architecture. You look at on-the-ground operational issues and work your way up.

The good thing about a bottom-up approach is that it allows architects to deal with current “as-is” situations which will require them to come up with creative and innovative yet pragmatic and viable solutions as opposed to some theoretical notions. Quick wins can be achieved compared to the lengthier top-down approach.

The downside to this approach however is the need to match the “as-is” solutions with the “to-be” requirements. A bottom-up approach, by its very nature, lacks the coordination and collaborative seamlessness that a top-down approach can envision. It is incumbent upon the architect to try to match individual solutions to the main structure. They need to be in sync.

Although the bottom-up approach is initially a faster process, it can take up a lot of time to achieve alignment with the overall vision because there is no broad overview involved. It is suitable for organizations that urgently need to resolve some operation issues.  

Blended approach
As mentioned earlier typically, Enterprise Architecture involves a top-down (or “to-be”) approach in order to formulate requirements for what is to be achieved under the big picture vision for the company.

The bottom-up approach is very fast and practical but there is a danger that it leads to too much focus on what is achievable and pragmatic as opposed to what is actually ideal and desirable. Too much emphasis on the “as is” may lead to a culture where the focus is on fixing and maintaining the current situation as opposed to building something new and better for the future.

Of course it doesn’t have to be an either/or situation. A blended approach with a mix of top-down and bottom-up approaches will provide the seamlessness, agility and speed that is necessary for the digital era. This is the approach we advocate for what we call Digital EA.

Aaron Tan Dani
Chairman of EA Chapter, Singapore Computer Society
aarontan@scs.org.sg