Deepening Students’ Knowledge Using Similarities & Differences

Even this comparison can be made more rigorous

By Scott Sterling

Just like a computer or office, the brain needs to organize information in a way that makes it easily accessible while enabling further growth. For example, if you can’t classify and find information related to the solar system, how are you supposed to understand astrophysics?

Students need to move from rote memorization to being able to discern pieces of knowledge and use the right bits to deepen their knowledge of the topic at hand. Examining similarities and differences is a great way to add rigor to your instructional practice.

It’s no surprise that comparing and contrasting make repeated appearances in both college and career readiness standards and pedagogies like Marzano’s Art and Science of Teaching framework. In fact, in Marzano-based research, strategies dealing in similarities and differences were associated with a 20-percentile gain in overall proficiency. Let’s look at how this actually works in the classroom.

First, tasks in the similarities and differences tree can be broken down into four categories:

  • Comparing
  • Classifying
  • Creating metaphors/similes
  • Creating analogies


Each of the four comes with numerous instructional techniques that help students assimilate the skills needed for that task.

New book from
Learning Sciences International

Examining Similarities & Differences: Classroom Strategies to Help Students Deepen Their Understanding

By Robert J. Marzano and Connie Scoles West


Recording & Representing Knowledge: Classroom Techniques to Help Students Accurately Organize and Summarize Content


In the classroom, the act of comparing two things often comes with a graphic organizer. Whether you use a t-chart, Venn diagram, Frayer model, or any other organizational scheme, the goal is for students to be able to organize their thoughts regarding the similarities and differences of two distinct things. As with most other techniques, it’s important for you to model effective practices and then gradually give control of the process to the students, eventually choosing what is to be compared and the criteria used.


Grouping items into similar categories helps students study a broad topic. For example, a biology class might group organisms based on their natural habitats. This not only aids students in information retrieval, but it also activates critical thinking skills because students have to think about what belongs in the group, what doesn’t, and why. Again, graphic organizers are often employed in these techniques.


We all remember lessons in English class about similes and metaphors. Can you remember which one uses “like” or “as” (similes)? There is a misconception that they can only be used in ELA classrooms. They work just as effectively at organizing similarities and differences in the other differences as the other tasks. In fact, getting facts that seem unrelated to fit the strict simile/metaphor model can add a constructive challenge.


Analogies are the classic comparison tool. Where the SAT questions fall short is that they do not ask the student to provide the relationship between the items being compared; making the comparison is only part of the goal. The student needs to be able to understand the arrangement for full comprehension. Make sure your students describe the relationship as well as provide the “A is to B as C is to D” structure.

What is your favorite similarities/differences activity? Why is it so effective? Share your thoughts with your colleagues in the Comments section.

For a learning techniques and analysis on the topic of similarities and differences, check out the latest book in the Essentials for Achieving Rigor series, Examining Similarities and Differences, now available in the Learning Sciences bookstore.

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