Definitions contain limited information

What is better than asking students for a definition?

When we decide what to ask students in a test, we should be thinking about what their answer will tell us. Answers contain information upon which we make inferences about a student’s knowledge. Questions and tasks prompt these answers, therefore we should ask questions which generate informationally rich responses.

It is not unusual for tests to ask students to define a term or concept: ‘Define photosynthesis’, ‘What is meant by longshore drift?’ or ‘What is a metaphor?’. However, these type of questions tend to generate informationally poor responses, ones that leave us with a great deal of uncertainty as to the student’s breadth and depth of understanding, and as to the flexibility of their knowledge.

There are two reasons definition questions tell us little. First, we do not know whether the student just learnt the definition by rote, with no real understanding of the concept. Second, even if we ask for the student to provide an example as part of their response, a definition does not reveal anything about whether they understand the boundaries of a concept or what would count as a non-example. In other words, can the student actually apply the concept to discern things about the world?

To illustrate this latter point, consider the following question and response:

Q. What is osmosis? Provide an example to illustrate your answer.

A. The movement of water through a semi-permeable membrane where the water has a higher concentration on one side than the other, until concentration is the same on both sides. For example, if a plant cell is placed in a solution with a higher concentration of water, water will move into the cell.

This answer may be awarded full marks because it identifies the key aspects of osmosis, namely that the direction of movement is from the area of higher concentration to the area of lower concentration, and that this will continue until there is equilibrium. The example provided is relevant and correct.

What if this student were presented with a situation in which gas replaced water? Would they recognise the movement of this gas through a membrane from a higher concentration to a lower concentration area as osmosis? It may be that the concept was only taught in the context of water movement, or perhaps specifically in relation to a plant cell being placed in a solution. If so, the student may not have generalised the concept beyond a specific example. If our goal is for students to recognise osmosis when they see it - for their learning to have value to them - a limited conception is not sufficient.

Let’s take another example:

Q,. Define ‘metaphor’?

A. A figure of speech in which a word or phrase is applied to an object or action to which it is not literally applicable.

Tick.

But it doesn’t take an English teacher to know that metaphors and similes are often confused. The student’s answer tells us nothing about whether this common ‘non-example’ is understood. Why is this important? The answer is that understanding why a simile is not the same as a metaphor reveals something important about what makes a metaphor a metaphor - that it asks the reader to imagine the object or action is the metaphorical subject rather than merely comparing a surface feature (by saying one thing is ‘like’ another). The power of a metaphor lies in this imaginative leap.

What is the alternative?

What can we do to generate more informationally rich answers; answers which reveal more about the student’s conceptual understanding?

Here are some alternative questions types we can use:

1. Contrast questions

Asking students to compare things helps tease out whether they understand the core tenets of a concept and where the boundaries are.

• Why is a metaphor more powerful than a simile?

• What is the difference between a public good and a semi-public good?

• What are the similarities and differences between the Favelas in Brazil and the shanty towns of South Africa?

2. Sorting questions

Asking students to place items in categories helps determine whether they can apply a concept to determine what counts as examples and non-examples.

• Which of the following uses photosynthesis? Leaf, grass, mushroom, frog, tree.

• Which of the following diagrams shows an obtuse angle?

• Place the following items under the correct heading: Animal, Vegetable, Mineral.

Such questions can be followed by another asking students to provide an explanation for one item they have selected and one they have not.

3. Multiple-choice: features of a concept

Asking students to identify the key features of a concept. The question should include a credible distractor answer/s.

Q. Circle which of the following are not fundamental features of a democracy.

a) Governance by consent of the people

b) Free and fair elections

c) Proportional representation in elections

d) The protection of human rights

e) The existence of a monarchy to balance the power of government

f) Freedom of association and assembly

g) The rule of law

4. Extraction questions

Asking students to extract examples and evidence from a text to test their ability to apply conceptual understanding.

• Identify three phrases in the text that suggest the author is despondent about the state of the UK economy.

• Circle five adjectives in the paragraph above.

• What evidence is there that Romeo is more reckless than Juliet?

5. Correction questions

Asking students to identify and explain errors in a definition or explanation tests how secure they are in their knowledge.

Q. Identify the error in the following explanation of the process of longshore drift:

“Longshore drift is the process by which sediment such as sand and pebbles moves along the coastline due to the action of waves approaching the shore at an angle. When waves (swash) hit the beach diagonally, they carry material up and across the shore. The backwash then moves the material back down the slope of the beach and out to sea, pulled by gravity. This zig-zag motion repeats, gradually transporting material.”

[The error is in the phrase ‘out to sea’]

None of the above questions are perfect, but then there is no such thing as a perfect assessment question. Each will reveal something different about a student’s knowledge. We need to decide what insights are most valuable and design questions which generate informationally rich answers. Asking students to define a term will only take us so far.