An independent tester is not influenced by the programmer when making the decision. In fact, more exploratory test can be performed depending on tester's experience and skills.

An independent tester can repeatedly find out more(other and different) defects than a tester working within(or attached to) 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 which often helps in exposing the hidden defects and problems in early phase.

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, worse yet due to lack of support from programmers.

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.

An independent tester will gain additonal communication skills and learn to build up a good team work with development team and other team members.

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 like a test manager and until becoming a good project manager with Quality-oriented.