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Lean and Mean Architecting with Risk- and Cost-Driven Architecture (RCDA)

May 2013 Presentation
Eltjo Poort (CGI)

A presentation from the ninth annual SATURN conference, held in Minneapolis, MN, April 29 - May 3, 2013.


Software Engineering Institute



Amid the abundance of software methodologies, there is a recent trend toward another paradigm for software development. Several groups from industry and academia are calling for a return to the essentials, or "lean and mean" models. This trend strongly resonates with the way CGI has been improving architecting practices since 2007.

CGI has developed Risk- and Cost Driven Architecture (RCDA) to support architects in a pragmatic, lean manner. RCDA consists of a set of principles and practices that have been harvested from practitioners' experiences, supplemented by insights from literature and research, and validated by CGI's architecture community.

RCDA contains guidance for architects on a more practical, solution-oriented level than enterprise architecture approaches, while being generic enough to help architect solutions that incorporate multiple technologies and architecture layers. Architects who try to apply a fixed architecting process (like TOGAF's ADM) often have problems fitting such a process in existing sales, design, and development processes. By separating architecting practices from the process, RCDA allows for broad usage of good architecting practices, without forcing teams to adopt a completely new process. RCDA's "best-fit practice" approach makes it easy for architects to apply its guidance in existing organizations. Hundreds of CGI architects have been trained in RCDA since 2010, and they report a significant positive impact on their architecting work.

Each RCDA practice set contains core practices and supporting practices:

  • In the Requirements Analysis practice set, the requirements originating from the stakeholders are prepared for shaping a solution.
  • The Solution Shaping practice set contains practices to define, document, and cost a solution's architecture based on the driving architectural concerns.
  • The Architecture Validation practice set contains practices aimed at validating the architecture developed in previous steps against the stakeholder's needs.
  • The Architecture Fulfillment practice set is about making sure that the architecture developed and validated in previous steps is now actually implemented in the solution in the most effective way.

Each RCDA practice contains a coordinated set of activities that can easily be integrated within existing design and development processes. Linked together, the RCDA core practices form a powerful CMMI-compliant architecting process. RCDA provides guidance on how to use the appropriate practices for every architecting situation and to omit practices that would just add waste in a particular context, making it a lean architecting approach.

RCDA is based on four key principles:

  1. Cost and risks drive architecture.
  2. Architecture should be minimal.
  3. Architecture is both blueprint and decisions.
  4. A solution architect is a decision maker.

These principles are applied throughout the individual RCDA practices, giving the approach conceptual integrity. The first principle—cost and risks drive architecture—gives the approach its name: the concerns that have the most impact on risk and costs have the highest architectural significance. This principle makes RCDA mean, enabling architects to focus on what really matters to their stakeholders. RCDA's workflow uses architectural concerns as a backlog prioritized by risk and cost, making RCDA agile and making it easier for architects to deal with change.