Utilitarianism is a little difficult to make valid because it depends on how the person looks at the situation and what they think is the right choice. There are also the different types of utilitarianism, which is act utilitarianism and rule utilitarianism. Act means the person will look at a specific act and determines if this act will indeed produce the greatest good overall. Rule means that a utilitarian may disagree in certain cases and then decide that as a rule, their disagreement will generate the greatest good for the greatest number. An example is an act utilitarian will see that cheating on a test is bad and it should not occur but on the other hand, a rule utilitarian could say that this specific act of cheating is okay because in the end more people will pass the test and there will be greater good for the greatest number.
I believe when dealing with utilitarianism, it is extremely easy to be bias because everyone can think of acts in different ways. Something that is extremely wrong for one person could be not too bad for