Exercising critical thinking: building a scale of evidence

Presentation of the activity

By developing their own “reliability scale,” inspired by the scientific method, they learn to rank types of evidence according to their reliability. Students will thus have to analyze each piece of information and rank the types of evidence according to a reliability criterion, from the weakest evidence to the most irrefutable evidence.

Objective : To show participants that not all clues and evidence on a given subject are equal.

Definition : What is the level of evidence?

In science, it is the ability of a study to answer a question. In the field of media and information literacy, there are several levels of evidence :

1 – Indices (low reliability) :

• Témoignage individuel rapporté
• Témoignage individuel direct
• Parole d’expert

2 – Preuves (fiabilité forte) :

• A case study that validates a hypothesis
• Several case studies that validate a hypothesis
• Study summaries
• Scientific consensus

However, even in cases of high reliability (scientific studies, case studies, etc.), it is important to maintain a critical mindset and remain cautious about the information you consult and use.

Activity schedule

1. Preparation for the exercise: Choose a scientific topic that may be subject to misinformation (e.g., climate change).
2. Preparation of the room: Draw a “reliability scale” on the board (see Appendix).
3. Distribute the proposals on paper to the participants, who will be asked to place them on the board on the “reliability scale.”

Example proposal :

• Scientific report by the International Panel on Climate Change
• My uncle told me that “global warming is not caused by human activity.”
• A scientist says on television that climate change is accelerating.
• US President Donald Trump says that “global warming does not exist.”
• Etc.

1. Correction : Once the participants have sorted the statements, the instructor will take some time to correct them and rearrange them in the correct order.
2. Grouping evidence : Next to the corrected reliability scale, participants will have to rank the statements by level of evidence as indicated in the exercise presentation.
3. Discussions : The exercise ends with a debate on the scientific method and critical thinking, and on the usefulness of this approach in the context of critical information processing (see SHEET 7 – Processing information critically).