Software Inspections

Defect Removal Efficiency

The number of defects found prior to releasing a product

divided byThe number of defects found prior to release plus the number reported by

customers during the first n months of actual use

times 100%

Objectives of an Inspection

Find problems at the earliest possible point in the software development process

Ensure that agreement is reached on rework that may need to be done

Verify that any rework done meets predefined criteria

Other Benefits of Inspections

Provide data on product quality and process effectiveness

Build technical knowledge among team members

Increase the effectiveness of software validation testing

Raise the standard of excellence for software engineers

Participants of an Inspection

Moderator – Coordinates the inspection and leads the discussion

Producer – Responsible for the work being inspected

Reader – Paraphrases the work inspected

Inspector – Inspects the product Recorder – Records problems discussed Manager – Supervises the producer

Responsibilities of the Moderator Understand the information being

inspected Lead the team in an effective discussion Mediate disputes Recognize key issues and keep the

team focused on them Maintain an unbiased view of the

information being presented Assign responsibilities appropriately

Responsibilities of the Producer Insure that the work product is ready for

inspection Make required information available on time Support the moderator in making meeting

arrangements, providing copies of materials, and establishing schedules for any required corrective action

Promptly resolve all problems identified Remain objective and avoid becoming

defensive

Responsibilities of the Reader

Be thoroughly familiar with the work product being inspected

Identify logical chunks of information and be able to paraphrase the information in each chunk to allow the moderator to keep the team focused on one chunk at a time

Support the moderator

Responsibilities of the Inspectors Be thoroughly familiar with the work product

being inspected as well as the appropriate documents and standards for the product

Identify discrepancies between the work product and applicable documents and standards

Focus on identifying problems, not solving them Remain objective Criticize the product not the producer Support the moderator

Responsibilities of the Recorder

Be thoroughly familiar with the work product being inspected

Record all issues raised by the team and ensure that they are recorded correctly

Record additional information as requested by the moderator

Support the moderator

Responsibilities of the Manager

Help decide what to inspect Include inspections in project schedules Allocate resources for inspections Support inspection training Participate in the selection of moderators Support the moderator in completing any

required rework

Attributes of a Good Process(according to SEI)

The process is written The process is flexible and can be changed Everyone agrees to follow the process The process includes metrics, which are used

to measure process efficiency Metrics are the basis for changing the process The process is actively managed

Institutionalizing InspectionsManagement Issues

Management must: Understand and support the objectives of

the inspection process Be willing to commit the resources

necessary to train inspectors Be willing to include inspections in project

schedules

Institutionalizing Inspections(Development Process Issues)

There must be: A written software development process or

one must be developed Management support for preparing a

software development process if it doesn’t already exist

A way to modify the process, if necessary, to include inspections at appropriate points

Active management of the process

Institutionalizing Inspections(Development Process Issues)

There must be: Support for inspections within the software

engineering organization An identification of potential obstacles to

the inspection process Resources available to train people in the

inspection process and a commitment to train new employees as they are hired

Institutionalizing Inspections(Inspection Metrics)

There must be: A definition of what product and process

metrics will be collected form inspections and how this data will be used

A continuous improvement process in place that identifies improvements to the inspection process based on collected data

Requirements Inspections

“If you can only afford to do one inspection on a project, you will get the biggest return on investment from a requirements inspection. A requirements inspection should be the one inspection that is never skipped.”

- Steven R. Rakitin

Why are Requirements Inspections Important?

Requirements are the most common source of problems in the development process

Requirements are written in English by people who typically have little or no training in writing software requirements

The English language is imprecise, ambiguous, and nondeterministic

Attributes of Good Requirements Specifications

Unambiguous Complete Verifiable Consistent Modifiable Traceable Usable

Requirements InspectionObjectives

Make sure each requirement in the Software Requirements Specification (SRS) is consistent and traceable to the document that preceded the SRS

Make sure each requirement in the SRS is clear, concise, internally consistent, unambiguous, and testable

Requirements InspectionPrerequisites

All inspection team members must receive appropriate training

The document(s) that preceded the SRS must have been reviewed and approved

The SRS must have been internally reviewed A requirements inspection checklist must be

available Guidelines for a good SRS must be available

A Sample Inspection Process

Planning Overview Meeting (optional) Preparation Inspection Meeting Follow-up

Objectives of Planning

Determine which work products need to be inspected

Determine whether a work product is ready for inspection

Identify the inspection team Determine whether an overview meeting

is necessary Schedule overview and inspection

meetings

Objective of Overview Meeting

Educate the inspection team on the work product being inspected and discuss the review material

Objective of Preparation

To be prepared for the inspection meeting by critically reviewing the review materials and the work product

Objective of the Inspection Meeting Identify errors and defects in the work

product being inspected

An error is a problem in which the software or documentation does not meet defined requirements and is found at the point of origin

A defect is a problem in which the software or its documentation does not meet defined requirements and is found beyond the point of origin.

Objective of the Follow-Up

Assure that appropriate action has been taken to correct problems found during an inspection