Code Quality Evaluation Guidelines

General Requirements

The general quality requirements are defined here as attributes of the solution that is to be evaluated ("The solution must be ...").

These attributes are grouped in four quality "levels" - a higher level representing a higher quality standard.

Projects can refer to these levels to define minimum quality goals, to prioritize certain quality aspects vs. other requirements, or to define an iterative approach of continuous quality improvement.

In order to pass a level, all criteria of this level and all previous levels must be met.

Level	Priority (MoSCoW)	Key Attributes	Description
0 - Experimental	-	-	any solution that does not (yet) meet all criteria of level 1
1 - Minimal	Must	valid, correct, safe	minimum standard for any solution
2 - Appropriate	Should	usable, maintainable, secure	minimum standard for production use
3 - Good	Can	integrated, configurable, robust	long-term development goals
4 - Optimal	Want	efficient, scalable, interoperable	optimization and enhancement goals

Level 1: Minimal

Valid

"Writing the right code"

• The specified solution solves the targeted problem and meets the minimum functional requirements

• The required input data are available in the target scenario

• The user actions required to apply and/or use the solution or its responses are possible in the target scenario

• All dependencies of the feature set are resolvable, and hardware and infrastructure requirements can be met in the target scenario

Correct

"Writing the code right"

• Processing does not fail for any valid input data or user action.

• All responses are correct for the respective input data or user actions according to the specification

Safe

• The solution does not break functionality of the application (except for functionality it replaces)

• All processing always ends with a valid database status regardless whether it succeeds or fails

• All failed processes are effectively removed from the system and their transactions properly rolled back

• The solution effectively prevents uncontrolled indefinite object or process proliferation

• The solution always returns to a defined system status after a failure so that the application remains accessible

Level 2: Appropriate

Secure

• The solution applies all relevant system configurations for authentication, authorization and accounting (AAA) appropriately and correctly.

• The solution does not allow the user to perform actions or initiate processes beyond the intended functionality.

Usable

• The solution can be used by the intended user group in the target scenario, i.e. the users can:
  • discover and access the features
  • understand and perform the required user actions
  • understand and control the consequences of actions
  • understand and provide the required type, quality and format of input data
  • discover and access the results, and apply them to achieve their goals

Maintainable

Level 3: Good

Integrated

Configurable

Robust

Level 4: Optimal

Efficient

Scalable

Interoperable

Advanced Criteria

The following advanced quality criteria that can be used to compare different solutions, or to define quality roadmaps beyond the standard criteria.

However, these advanced criteria do not enhance the general quality levels: a level-2 solution is still of lower quality than a level-3 solution - regardless how many advanced criteria the level-2 solution fulfills.

Stable

Appealing

Flexible

Standardized

Extensible

Generic

Customizable