Automated testing is the preferred testing method for a number of reasons, such as faster turnout time and allowing multiple attempts with increasing variance. If there’s anything that defines the essence of automated testing, however, it’s the fact that it removes the human factor out of the equation, albeit not entirely.
To say that human error could affect the results of the test is debatable. If a person performs a task frequently enough, whether it’s right or wrong, it would become a habit. In terms of testing, a human tester may see an error often enough and don’t do something about it because he or she may have considered it normal based on past processes.
With an automated tester, tests can be conducted over and over with clean slates. It may keep a record of past results, but it won’t use them to conduct subsequent tests. It will also classify errors with extreme prejudice. A simple typo is a legitimate error to the automated tester although it may be an acceptable oversight to the human.
When your clients rely on you to produce the most powerful software your resources can make, there is basically no room for error. An automated tester is designed for this purpose.