Gap Analysis step by step: the matrix

A validation technique

In the ADM, Gap Analysis is used to validate an architecture under development. It brings out what is missing between the Baseline Architecture and the Target Architecture: items left out on purpose, forgotten by mistake, or not yet defined.

From the techniques perspective, its aim is to document the difference between the two states, that is, the building blocks added, removed, or changed. It is used while developing the domains (Phases B, C, and D), and its results are consolidated in Phase E to define the implementation work.

Building the matrix

The approach follows a few simple steps, which can be applied domain by domain.

• Put the Baseline ABBs in rows and the Target ABBs in columns
• Add a final ‘New’ row on the Baseline side and a final ‘Eliminated’ column on the Target side
• Mark ‘Included’ when an ABB appears in both architectures
• Review each Baseline ABB missing from the Target
• Mark in the ‘New’ row each Target ABB missing from the Baseline

Reading the cells

A Baseline ABB missing from the Target may have been rightly eliminated: it is then marked in the ‘Eliminated’ column. If it was forgotten, it is an accidental omission, corrected by reinstating it in the Target in the next iteration.

A Target ABB with no equivalent in the Baseline is a gap: it will have to be developed or procured. When two items are similar but not identical, such as telephony services and enhanced telephony services, the cell flags a potential match to examine.

At the end of the exercise, everything under ‘Eliminated’ or in ‘New’ is a gap: either it is justified as a correct elimination, or it must be addressed by reinstating, developing, or buying.

Beyond applications

The matrix is not limited to IT services. Gaps can be sought in people and skills, processes, timely data availability, or infrastructure. The gaps retained then feed the candidate components of the Architecture Roadmap, and later the Work Packages.