This task compares an existing architecture to a target architecture in order to define the gaps and fit. This is then used in follow-on planning, such as migration planning.
Gap analysis consists of comparing the present state and the desired end or 'target' state and deriving and
describing the gap between them. This 'gap' description is then used, along with other analysis, to derive a migration
plan—the plan from migrating from the current state to the target state through a series of steps, which in the IT
architecture context means through a series of projects and project releases. The purpose of gap analysis is to:
Identify the differences between the architectural components and patterns of existing solutions and those of the
target architecture;
Document these differences;
Prioritize these differences as an aid to the next steps.
In information technology, gap analysis is the study of the differences between two different IT architectures, usually
for the purpose of determining how to get from one state to a new state. A gap is sometimes spoken of as "the
difference between where we are and where we want to be." Gap analysis is undertaken as a starting point for
figuring out how to bridge that space; how to migrate in a logical and low risk way to the new state. A model
of the target architecture is created, now we need to analyze the model in relation to the current
architecture to aid in the transition from one to the other.
The steps involved in doing a gap analysis are:
Define the scope of the analysis, if not clear from the architecture in question (i.e. the Context and
Scope);
Create an "existing architecture" description if needed;
Create an "target architecture" description if needed;
Collect all documentation of the existing environment and the target architecture;
Compare the current environment's Entity, Processes, Location and Roles Models to those identified in the
target;
Find and describe the gaps;
Prioritize the gaps that were identified based upon stakeholder priorities, practicalities of migration, and
the state of the current environment.
The output is a prioritized summary of areas that need to be transformed in order to achieve the target architecture.
The areas requiring work have priorities applied based upon stakeholder need for new or changed functionality. These
priorities are adjusted, if needed, based upon the state of health of these components in the current environment. This
assessment is then used as input to the development of the migration plan.
Steps
Identify Components
Depending on the objectives and level of the gap analysis (i.e., Business, Logical or Technology level) and
the scope (i.e., Enterprise, Business Line, Business Unit or Project) adjust the focus of this activity to suit.
This first step involves a review of the existing architecture, or project documentation of existing assets. The
architectural components, in terms of entities, processes, locations and actors/roles are identified. Similarly the
components at the Logical and / or Technology layers are identified and documentation extracted (i.e.
logical/technical data, logical/technical processes, logical/technical locations and logical/technical roles).
Architectural patterns are also identified (e.g., n-tier or client-server, etc.).
A similar analysis of the target architecture is performed, resulting in a list of components, structures and
patterns to be compared in the next step.
Document Gaps
This documentation step involves more than just simply documenting new components or capability. In is essential that
differences in how components perform their tasks is understood, and that differences in processes are identified, or
even minor differences in entity (data) definitions. These differences can be categorized into one of the following:
New - new data, functions, process or roles
Change - a change in the data, functions, process or roles
Delete - a deleted data, function, process or role
Relationships between these components (i.e., data, function, process and role) are also identified and documented
in order to understand dependencies that need to be address during the migration.
Prioritize Gaps
The complete picture is then analyzed, with the aid of stakeholders, in order to refine the understanding of these
differences and to define priorities. These priorities are based upon two aspects:
Business Needs - it is the new or updated functionality is a priority for the business;
State of Existing - the state, in terms of maintainability and reliability and cost of existing
components.
These two aspects of each gap are evaluated and a relative priority assigned to the gap. A three level priority
(i.e., High, Medium, Low) scheme is recommended.
A complementary analysis needs to be performed as well, namely an analysis based upon component dependencies and
implementation and migration considerations. This analysis, along with an understanding of the defined priorities, is
in essence results in the information at the core of a migration plan—thus the Gap Analysis documentation produced
here is a key input into the development of a Migration Plan.
