The degree of independence avoids author bias and is often more effective at finding defects and failures.

There is several level of independence which is listed here from the lowest level of independence to the highest:
i. Tests by the person who wrote the item.
ii. Tests by another person within the same team, like another programmer.
iii.Tests by the person from some different group such as an independent test team.
iv.Tests by a person from a different organization or company, such as outsourced testing or certification by an external body.

When we think about how independent the test team is? It is really very important to understand that independence is not an either/or condition, but a range:

• At one end of the range lies the absence of independence, where the programmer performs testing within the programming team.
• Moving toward independence, we find an integrated tester or group of testers working alongside the programmers, but still within and reporting to the development manager.
• Then moving little bit more towards independence we might find a team of testers who are independent and outside the development team, but reporting to project management.
• Near the other end of the continuum lies complete independence. We might see a separate test team reporting into the organization at a point equal to the development or project team. We might find specialists in the business domain (such as users of the system), specialists in technology (such as database experts), and specialists in testing (such as security testers, certification testers, or test automation experts) in a separate test team, as part of a larger independent test team, or as part of a contract, outsourced test team.

Benefits of independence testing:

• An independent tester can repeatedly find out more, other, and different defects than a tester working within a programming team – or a tester who is by profession a programmer.
• While business analysts, marketing staff, designers, and programmers bring their own assumptions to the specification and implementation of the item under test, an independent tester brings a different set of assumptions to testing and to reviews, which often helps in exposing the hidden defects and problems
• An independent tester who reports to senior management can report his results honestly and without any concern for reprisal that might result from pointing out problems in coworkers’ or, worse yet, the manager’s work.
• An independent test team often has a separate budget, which helps ensure the proper level of money is spent on tester training, testing tools, test equipment, etc.
• In addition, in some organizations, testers in an independent test team may find it easier to have a career path that leads up into more senior roles in testing.

Risks of independence and integrated testing:

• There is a possibility that the testers and the test team can get isolated. This can take the form of interpersonal isolation from the programmers, the designers, and the project team itself, or it can take the form of isolation from the broader view of quality and the business objectives (e.g., obsessive focus on defects, often accompanied by a refusal to accept business prioritization of defects).
• This leads to communication problems, feelings of unfriendliness and hostility.
• Lack of identification with and support for the project goals, spontaneous blame festivals and political backstabbing.
• Even well-integrated test teams can suffer problems. Other project stakeholders might come to see the independent test team – rightly or wrongly – as a bottleneck and a source of delay. Some programmers give up their responsibility for quality, saying, ‘Well, we have this test team now, so why do I need to unit test my code?’

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