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@@ -75,7 +75,7 @@ Thu, Feb 15 | [Qualitative analysis in the age of LLMs](pages/feb15-coding-with-
 Tue, Feb 20 | [Project proposal presentations](pages/feb20-proposals.md) | [slides](slides/10-proposals.pdf)
 Thu, Feb 22 | [Types of errors in probability survey research](pages/feb22-surveys-pt1.md) | [slides](slides/11-survey-design-pt1.pdf)
 Tue, Feb 27 | [Questionnaire design and multi-item scales](pages/feb27-surveys-pt2.md) | [slides](slides/12-survey-design-pt2.pdf)
-Thu, Feb 29 | Experimental design | 
+Thu, Feb 29 | [Experimental design](pages/feb29-causal-relationships.md) | [slides](slides/13-experiments-pt1.pdf)
 ~~Tue, Mar 5~~ | ~~Spring break, no class~~ |
 ~~Thu, Mar 7~~ | ~~Spring break, no class~~ |
 Tue, Mar 12 | Experimental design (part III) | 
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+## L13: Experimental Design Part I - Causal Relationships ([pdf](../slides/13-experiments-pt1.pdf), [video]())
+
+[![Lecture13-Experiments](../assets/images/13-experiments-pt1.jpg)](../slides/13-experiments-pt1.pdf)
+
+This lecture is the first part of a series on designing experiments. We discussed what it means for something to be a "cause" or an "effect," the three ingredients needed for establishing a causal relationship, and how experiments as a research method match the characteristics of causal relationships very well.
+
+We also discussed within-vs-between subjects designs and their trade-offs.
+
+
+### Lecture Readings
+
+> Shadish, W. R., Cook, T. D., & Campbell, D. T. (2002). Experimental and quasi-experimental designs for generalized causal inference. Wadsworth Publishing.
+
+The discussion of cause as an *inus condition* -- "insufficient but nonredundant part of an unnecessary but sufficient condition" -- follows Chapter 1 from the book (Experiments and generalized causal inference).
+
+
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