Assessing Critical Thinking in the Science Classroom

Paula Lemons

The University of Georgia

September 26, 2008

For this workshop “assessment” is

Any tool used to measure students’ knowledge or skills

Examples: exam questions, writing assignments, oral presentations, etc.

I hope you will . . .

Connect with others who are interested in assessing critical thinking.

Become familiar with one method for preparing critical-thinking assessments.

Gain a process for critiquing your own assessments to determine if they are actual measures of critical thinking.

A Question to Consider

What comes to mind when you think about “critical thinking in the science classroom?”

My courses lacked

Any proof that my assessments were real measures of critical-thinking skills.

I needed

1. An explicit definition of critical thinking.

2. A systematic way to recognize and reward critical thinking.

A Take Home Point

Assessing critical thinking involves specifying critical-thinking goals linking them to course grading

plans This is not simple!

What method can we use?

Define the critical-thinking skills we want students to develop.

Design assignments that require these skills.

Think, in advance, about grading i.e., How will we look for and reward

not only content knowledge but also critical-thinking skill?

Bloom’s Taxonomy of Educational Objectives*

*From Bloom, B. S., ed. 1956. Taxonomy of Educational Objectives: The Classification of Educational Goals. McKay, New York.

mRNA

Choice 1. mRNAs diffuse through the nuclear membrane.

Nuclear membrane

NucleusCytoplasm

Nuclear membrane

Nucleus

mRNA

Cytoplasm

Choice 2. mRNAs move through a channel in the nuclear membrane that is created by a protein.

Example: mRNA diffusion through a nuclear membrane.

In eukaryotes mRNAs must travel through the nuclear membrane (a double lipid-bilayer) to the cytoplasm in order to be translated into proteins. Based on what you know about the chemical structure of mRNA and of lipid bilayers, choose the picture below that you think more accurately models the movement of mRNAs. Explain the rationale for your choice. (6 points)

Choice: ______ Rationale:

Knowledge needed to answer question: • Chemical structure of mRNA and lipid bilayers.

Critical thinking skills needed to answer the question: • Application – Students must address mRNA movement in the cell using knowledge of mRNA structure and lipid bilayers. • Analysis – Students must examine both scenarios and decide which is more

likely to be the way that mRNA moves from nucleus to cytoplasm.

Complete answers will include each of the following: I Chemical structure of biomolecules:

IA mRNA – charged or polar molecule IB lipid bilayer – hydrophobic interior (NOTE: mentioning the hydrophilic head groups is not essential to this answer).

II Point out that the lipid bilayer cannot accommodate a charged molecule via diffusion, thereby eliminating Choice 1. III Point out that since diffusion won’t work, an alternative mechanism is needed. Therefore, Choice 2 is correct (mRNAs move

through a protein channel).

Grading rubric

Knowledge component Critical thinking components

Evaluating sample assignments What, if any, content knowledge is required? What, if any, critical-thinking skills are

required? Define these skills as explicitly as possible.

Is it possible to come up with a correct and complete answer if you have the content knowledge but not the critical-thinking skill?

Is it possible to come up with a correct and complete answer if you lack the content knowledge but have the critical-thinking skill?

What else do you observe about these questions?

What are the benefits of systematically assessing CT?

Provides data about The source of student errors (content vs.

critical thinking) Misconceptions about concepts

Example: mRNA diffusion through a nuclear membrane.

36% of students selected choice 2 – mRNA moves through channel – with either no rationale or an incorrect rationale.

Follow-up question – similar but molecule was uncharged.

43% of students said that the uncharged molecule would need a channel for transport.

Question: What is driving this error in student answers? (1) Misconceptions about membrane transport? and/or (2) A mistake in the way material is presented?

What are the benefits of systematically assessing CT? Provides data about

The source of student errors (content vs. critical thinking).

Misconceptions about concepts. Clarifies course expectations for students

e.g., through review of valid critical-thinking questions and rubrics in class; discussion of specific CT expectations in class, in office hours, on syllabus

Provides a framework for instructors to make decisions about content, assignments, readings, etc.

Special Thanks to . . .

Dr. Ahrash Bissell, ccLearn Dr. Jeremy Hyman, Western Carolina

University This work has been supported by

Arts and Sciences Council on Faculty Research, Duke University.

Trinity College of Arts and Sciences, Duke University.