When assembling a test team to work on an enhancement to an existing system, which of the following has the highest level of test independence?

The correct choice highlights the concept of test independence, which is fundamental to effective testing practices. Test independence refers to the objectivity and unbiased nature of testing when the individuals involved are not part of the development process or previously engaged with the system being tested. A contract tester who has never worked for the organization before embodies the highest level of this independence.

This tester brings a fresh perspective to the enhancement project, enabling them to evaluate the application without any preconceived notions or biases stemming from prior experiences within the organization. Their lack of prior involvement with the system or existing interpersonal relationships within the team allows them to focus purely on identifying potential issues or defects, thus contributing to a more thorough and impartial assessment.

The other options represent various degrees of involvement with the system or the development process, which could introduce biases into the testing effort. For example, a business analyst who wrote the original requirements may have a vested interest in how the system functions according to those requirements. Similarly, a permanent programmer familiar with the code—whether they reviewed it or not—might have an inherent bias towards the new implementation based on their past coding experiences. A permanent tester, even though experienced in finding defects, still brings prior knowledge of the system that might influence their testing approach.

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