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.
