Turning Bottom-Up Upside Down

Joe McKendrick recently had a post regarding bottom-up approaches to SOA in response to this post from Nick Malik of Microsoft, which was then followed up with another post from Nick. I was going to post solely on this discussion, when along came another post from James McGovern discussing bottom-up and top-down initiatives. While James’ post didn’t mention any of the others, it certainly added to the debate. Interestingly, in his post, James put SOA in a “bottom-up” list. Out of this, it seems like there are at least three potential definitions of what bottom-up really is.

Joe’s discussion around “bottom-up” has a theme of starting small. In his followup post, Nick actually concurs with using this approach to SOA, however, he points out that this approach is not what he considers to be “bottom-up.” For the record, I agree with Nick on this one. When I think of bottom-up in the context of SOA, I think of individual project teams building whatever services they want. This puts the organization at great risk of just creating a bunch of services. While you’re guaranteed that your services will have at least one consumer by simply identifying them at the time they’re needed within a project, this is really the same way we’ve been building systems for years. If you change the approach to how you build the solution from the moment the service is identified, such as breaking it out as its own project with an appropriate scope increase to address broader concerns, you can still be successful with this approach, but it’s not easy. When I think of top-down, like Nick, it also starts to feel like a boil the ocean approach, which is probably at just as big of a risk of being unsuccessful.

Anyway, now bringing James’ post into the discussion, he had given a list of three “top-down” IT initiatives and three “bottom-up” initiatives. Top-down ones were outsourcing, implementing CMMi and/or PMI, and Identity Management within a SoX context. The bottom-up initiatives were SOA, Agile Methods, and Open Source. By my interpretation, James’ use of the terminology refers more to the driving force behind the effort when mapped to the organization chart. His top-down efforts are likely coming from the upper echelons of the chart, while the bottom-up efforts (although SOA is debatable) are driven from the lower levels of the chart. I can certainly agree with this use of the terminology, as well.

So is there any commonality? I think there is and it is all about scope. The use of the term top-down is typically associated with a broad but possibly shallow focus. The use of the term bottom-up is typically associated with a narrow but possibly deep focus. What’s best? Both. There’s no way you can be successful with solely a bottom-up or top-down approach. It’s like making financial decisions. If you live paycheck to paycheck without any notion of a budget, you’re always going to be struggling. If you develop an extensive budget down to the penny, but then never refer to it when you actually spend money, again, you’re always going to be struggling. Such is the case with SOA and Enterprise Architecture. If you don’t have appropriate planning in place to actually make decisions on what projects should be happening and how they should be scoped, you’re going to struggle. If the scope of those projects is continually sacrificed to meet some short term goal (typically some scheduling constraint), again, you’re going to struggle. The important thing, however, is that there does need to be a balance. There aren’t too many companies that can take a completely top-down approach. Even startups with a clean IT slate are probably under such time-to-market constraints that many strategic technology goals must be sacrificed in favor of the schedule. It’s far easier to fall in the trap of being overweighted on bottom-up efforts. To be successful, I think you need both. Enterprise architects, by definition, should be concerned about breadth of coverage, although not necessarily breadth of technology as specializations do exist, such as an Enterprise Security Architect. An application architect has narrower breadth than an enterprise architect, but probably more depth. A developer has an even narrower breadth, but significant depth. The combination of all of them are what will make efforts successful both in the short term and in the long term.

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