6.2 Hill's Criteria

Learning Goals

[Link to PlayPosit]

[Link to instructional video]

More details

After this lesson, students should

1. Identify cases in which “ideal” experiments are not possible, due to ethical or practical constraints.
2. For a given scenario in which a causal hypothesis/claim is being made, identify plausible alternative hypotheses that could be consistent with the data.
3. Identify additional sources of evidence that could be used to help mitigate flawed experiments, including prior plausibility, dose-response relationships, specificity, temporal ordering, and multiple consistency across contexts.
4. Recognize when causal evidence in the absence of an RCT can be fairly compelling, especially if there are many different types of evidence combined.

Definitions

Hill's criteria:

• Prior plausibility

  Can a plausible mechanism be constructed, or is there some other basis for interpreting the current evidence in terms of one causal structure over another, such as data from other studies?

• Temporality/temporal sequence

  Did the hypothesized cause precede the effect?

• Specificity

  Specific predictions for specific consequences that have come true are less likely to be caused by other factors.

• Dose-response curve

  Do the quantities of the hypothesized cause correlate with the quantity, severity, or frequency of the hypothesized effect across ranges?

• Consistency across contexts

  Does the correlation appear across diverse contexts?

Common Misconceptions

• Since we can't run a randomized controlled trial on whether CO2 emissions cause global warming, we can't ever know whether it does.

  A non-RCT study can still be serve as potentially weaker, but sometimes just as strong, evidence for causation.

• Students are quick to notice small sample size, slower to notice problems with experimental design.
• Students struggle to generate non-RCT types of evidence for causality, although they are better at recognizing it.
• Identifying natural experiments is also difficult, probably because many students find the principles of RCTs slippery.

Context

[Explanation of how the current topic into the larger context of the course by explaining how the previous topic(s) relate to the current topic and leaving cliffhangers for future topics where relevant throughout the lesson]

Before

X.X Lesson Name

Explanation.

• Itemized explanation.

After

X.X Lesson Name

Explanation.

• Itemized explanation.

Recommended Outline

Before Class

• [Any essential logistical things that need to be done for this class]
• Prepare a seating chart.
• Review PlayPosit and discussion questions and ask faculty, Gabriel, or Emlen any questions you have.
• (Optional) Prepare a presentation.

During Class

• (5 min) Come up with some fun way to assign the roles of spokesperson and notetaker (e.g. earliest birthday in the year, lives furthest from campus). Remind them of the responsibilities of these roles.
• ([#] min) [Description of some module from #Lesson Content]
• (5 min) Collect questions for plenary.

Lesson Content

Clicker Question

1. Question
   1. Option 1
   2. Options 2

Activity 1: Name

[Brief description of and motivation for the activity]

Discussion Questions

1. Question 1
   1. Subquestion a

   2. Subquestion b

Collect Questions for Plenary

(5 min) Collect remaining questions from the students for faculty in plenary (can be questions for clarification, extension, discussion, etc.), and add [ here].