Boehm’s Software Quality Model

In 1978, B.W. Boehm introduced his software quality model. The model represents a hierarchical quality model similar to the McCall Quality Model to define software quality using a predefined set of attributes and metrics, each of which contributes to the overall quality of software. The difference between Boehm’s and McCall’s Models is that McCall’s Quality Model primarily focuses on precise measurement of high-level characteristics, whereas Boehm’s Quality Model is based on a wider range of characteristics.

Example: Characteristics of hardware performance, that are missing in McCall’s Model. Boehm’s model has three levels for quality attributes. These levels are divided based on their characteristics. These levels are primary uses (high-level characteristics), intermediate constructs(mid-level characteristics), and primitive constructs(primitive characteristics).

Primary Uses of Boehm’s Model

The highest level of Boehm’s model has the following three primary uses stated as below –

1. As is the utility: The extent to which, we can use software as-is.
2. Maintainability: Effort required to detect and fix an error during maintenance.
3. Portability: Effort required to change the software to fit in a new environment.

Quality Factors Associated with Boehm’s Model

The next level of Boehm’s hierarchical model consists of seven quality factors associated with three primary uses, stated below –

1. Portability: Effort required to change the software to fit in a new environment.
2. Reliability: The extent to which software performs according to requirements.
3. Efficiency: Amount of hardware resources and code required to execute a function.
4. Usability (Human Engineering): Extent of effort required to learn, operate and understand functions of the software.
5. Testability: Effort required to verify that software performs its intended functions.
6. Understandability: Effort required for a user to recognize a logical concept and its applicability.
7. Modifiability: Effort required to modify software during the maintenance phase.

Boehm further classified characteristics into Primitive constructs as follows- device independence, accuracy, completeness, consistency, device efficiency, accessibility, communicativeness, self-descriptiveness, legibility, structuredness, conciseness, and augment-ability. For example- Testability is broken down into:- accessibility, communicativeness, structuredness, and self-descriptiveness.

Questions for Practice

1. COCOMO Model is used for [UGC-NET 2008]

(A) product quality estimation           

(B) product complexity estimation     

(C) product cost estimation                

(D) all of the above

Solution: Correct Answer is (C).

Explanation: COCOMO Model is the model which was developed by B.W. Boehm that estimates the procedural cost model of software.

2. In a Software Project, COCOMO (Cost Constructive Model) is used to estimate [GATE CS 2004]

(A) Effort and Duration based on the size of the Software

(B) Size and Duration based on the effort of the Software

(C) Effort and Cost based on the duration of the Software

(D) Size, Effort, and Duration based on the cost of the Software

Solution: Correct Answer is (A).

For More, refer to COCOMO Model.

FAQs on Boehm’s Quality Model

1. What is Boehm Model?

Answer:

Boehm’s Model is a type of software model that is used to define software quality on the basis of certain parameters.

2. Where is Boehm’s Model Used?

Answer:

Boehm’s Model is used to represent a hierarchical model that has the structure around the high level characteristics, intermediate and primitive characterisitcs.

3. Which model is best for Software Quality?

Answer:

One of the most widely used and most recognized model is ISO/IEC 25010.