Social assumptions of intelligence tests are that the cognitive ability of an individual can be measured objectively and compared to others, aiding in the identification of needs or strengths that may result in labeling, stereotyping, or the failure to notice other abilities not tapped by the test. Knowledge tests, on the other hand, assume that learning is homogeneous and that all students should know the same things, thus aiding in progress monitoring but also putting a learner at a disadvantage when the backgrounds or learning styles of the students are different. An alternative assessment example is portfolio assessment, whereby students over time assemble work samples, reflections, and projects that demonstrate growth and understanding. This has much value for authentic learning, creativity, and progress, holistic in nature as it looks at the student's abilities, though very time-consuming and subjective if rubrics are ill-defined, and so difficult to compare across students.