When writing a claim you need to take a stance on a particular issue. In this case the issue is whether or not "standardized tests are the proper measuring sticks for student performance." This stance should be the first part of your claim. Then follow it up with "because..." and your three reasons.
For example, Standardized tests are a proper measuring stick for student performance because they can test a student's knowledge on a wide range of subjects, they are the same for everyone, and they are an accurate indicator of how well a student will do in their future studies especially for fields like medicine and law.
What text are you talking about?
This story is about a boy name Logan struggling with life as a young adult when his family learns he is homosexual. Logan is a child and he is living with his mother. He had no memory of his father. His mother then marries a man named George who is a mechanic.
In Harrison Bergeron, the function of the agents is to ensure equality among all people.
To this end, they are responsible for handicapping every individual. These agents are also responsible for making sure the handicapping laws are being followed. When the laws are not being followed -- if George were to remove some of the weights around his neck, for example -- the agents would punish him for breaking the law.