A Closer Look at Assessment in Science


In a commencement address at Western New England University in 2012, astrophysicist Neil deGrasse Tyson provided this parable…students are asked to give the correct spelling of the word “cat.”  One student spells it correctly as “C-A-T”. The second student spells it “K-A-T” and the third as “X-Q-W.” He then makes the profound statement – “Do you realize that [“X-Q-W”], is marked equally as wrong as the K-A-T?”

Think about the assessments you ask students to complete – not just summative assessments, but formative ones as well.  Do you have an answer key that shows there is only one right answer? Or, is it possible that some of the answers are “more wrong” than others?  Students are becoming increasingly fearful of doing their own thinking because they have, for nearly all of their educational careers, been lead to believe that the only answer that matters is the answer the teacher wants.  This type of thinking leads students to make comments such as, “Am I doing this right?” “Is this how I’m supposed to do this?” They see their role as “answerers” of questions, and the teacher’s role as “questioner.” 

Assessments with only one right answer are, very possibly, assessing at a surface level – perhaps focusing on vocabulary or simple recall.  For example, consider an assessment question such as this one: 

Which one of these is not a type of friction? writing at desk
      A. static friction
     B. Sliding friction
     C. Fluid friction
     D. Potential friction 

This question will identify those students who know the definitions of the types of friction, but it won’t tell the teacher if they have a deep understanding of friction and how it impacts a system.  

Consider the following prompt, also related to friction: 

Susan was roller skating on her sidewalk and hit a small rock, which caused her to fall down and scrape her knees.  Identify at least 3 types of friction that would have occurred in that scenario and explain where they occurred. Then, draw a picture that shows the parts of system described in the scenario and the interaction of the forces in the system.  (Please note this is listed as an example and not intentionally aligned to any particular performance expectation.)

In order to assess the above prompt, a teacher would need to determine how a student would respond at each level of understanding of the concept; full, partial and limited.  

How might a student who has a full understanding respond to the prompt?
How might a student who has a partial understanding respond to the prompt?
How might a student who has a limited understanding respond to the prompt?  

By identifying these levels, a teacher can not only more accurately identify each student’s level of understanding, but can also determine how well the prompt aligns with the intended performance expectation.   

When we look at the purpose of assessments, to determine a student’s understanding (or lack of), the second example provides a teacher a more accurate view of a student’s understanding of how friction impacts the interactions of forces within a system.
Consider your own assessments and reflect on the assessments you gave students today.  What about the assessments you planning to use tomorrow to assess students understanding this week’s lesson?  Take a close look and ask yourself if you are asking students to demonstrate their understanding at a deep level or if you are assessing their ability to recall surface-level information.  If you want to learn more about developing assessments that are aligned to the Next Generation Science Standards, consider reading STEM Teaching Tool #29 – Steps to Designing a 3D Assessment