Class 4: Measuring stuff and DAGs

# In-person session 4

**February 3, 2022**

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# Plan for today

.box-4.medium.sp-after-half[Quick useful R tips]

.box-2.medium.sp-after-half[Measuring outcomes]

.box-5.medium.sp-after-half[DAGs]

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layout: false
name: r-stuff
class: center middle section-title section-title-4 animated fadeIn

# Quick useful R tips

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.box-4.large[Visual markdown editor]

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.box-4.large[Weird figure/table placement in PDFs]

???

https://bookdown.org/yihui/rmarkdown-cookbook/figure-placement.html

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.box-4.large[Word count]

???

<https://github.com/benmarwick/wordcountaddin>

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.box-4.large[Figure and table captions and numbers]

???

- <https://bookdown.org/yihui/rmarkdown-cookbook/figure-number.html>
- <https://rmd4sci.njtierney.com/figures-tables-captions-.html>
- <https://rmd4sci.njtierney.com/start.html>

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.box-4.large[DAGs in R vs. Dagitty]

???

<https://evalsp22.classes.andrewheiss.com/example/dags/>

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layout: false
name: outcomes
class: center middle section-title section-title-2 animated fadeIn

# Measuring outcomes

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# Outcomes and programs

.box-2.medium[Outcome variable]

.box-inv-2.sp-after-half.SMALL[Thing you're measuring]

.box-2.medium[Outcome change]

.box-inv-2.sp-after-half.SMALL[∆ in thing you're measuring over time]

.box-2.medium[Program effect]

.box-inv-2.SMALL[∆ in thing you're measuring over time *because of* the program]

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# Outcomes and programs

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.box-2.large[Abstraction]

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layout: false
name: dags
class: center middle section-title section-title-5 animated fadeIn

# DAGs

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.box-5.medium[You keep saying that causal inference lets you "legally" make causal claims.]

.box-5.medium[Are there actual legal consequences if you make a causal claim without specific language?]

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.box-5.large[Causal thinking is necessary— even for descriptive work!]

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]

???

Necessity of causal thinking: Mention the McElreath tweet on birth certificate introduction and death ages: <https://twitter.com/rlmcelreath/status/1427564280744976384>

<https://www.biorxiv.org/content/10.1101/704080v2>

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.box-5.less-medium["Every time I get a haircut, I become more mature!"]

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.box-5.less-medium["Every time I get a haircut, I become more mature!"]

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.box-5.less-medium[Getting older opens a backdoor path]

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.box-5.medium[But what does that mean, "opening a backdoor path"?]

.box-5.medium[How does statistical association get passed through paths?]

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.box-5.less-medium.sp-after[How do I know which of these is which?]

.center[
<figure>
 <img src="img/05-class/dag-associations.png" alt="DAG associations" title="DAG associations" width="100%">
</figure>
]

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.pull-left[
<figure>
 <img src="img/04-class/slider-switch-plain-80.jpg" alt="Switch and slider" title="Switch and slider" width="100%">
</figure>
]

.pull-right[
<img src="04-class_files/figure-html/confounding-dag-alone-1.png" width="100%" style="display: block; margin: auto;" />
]

---

.pull-left[
<figure>
 <img src="img/04-class/slider-switch-plain-80.jpg" alt="Switch and slider" title="Switch and slider" width="100%">
</figure>
]

.pull-right[
<img src="04-class_files/figure-html/mediating-dag-alone-1.png" width="100%" style="display: block; margin: auto;" />
]

---

.pull-left[
<figure>
 <img src="img/04-class/slider-switch-plain-80.jpg" alt="Switch and slider" title="Switch and slider" width="100%">
</figure>
]

.pull-right[
<img src="04-class_files/figure-html/colliding-dag-alone-1.png" width="100%" style="display: block; margin: auto;" />
]

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.box-5.medium[d-separation]

.box-inv-5[Except for the one arrow between X and Y, no statistical association can flow between X and Y]

.box-inv-5[This is **identification**— all alternative stories are ruled out and the relationship is isolated]

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.box-5.large[How exactly do colliders mess up your results?]

.box-5.medium[It looks like you can still get the effect of X on Y]

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.center[
<figure>
 <img src="img/04-class/facebook.png" alt="Facebook collider" title="Facebook collider" width="55%">
</figure>
]

???

<https://www.businessinsider.com/facebook-sent-incomplete-misinformation-data-flawed-researchers-2021-9>

<https://www.nytimes.com/live/2020/2020-election-misinformation-distortions#facebook-sent-flawed-data-to-misinformation-researchers>

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# Does niceness improve appearance?

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]

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# Collider distorts the true effect!

]

]

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.box-5.large[Effect of race on police use of force using administrative data]

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.box-5.medium[Effect of race on police use of force using administrative data]

.pull-left[
<figure>
 <img src="img/05-class/klm-dag.png" alt="Use of force" title="Use of force" width="100%">
</figure>
]

.pull-right[
<figure>
 <img src="img/05-class/klm.png" alt="Use of force" title="Use of force" width="100%">
</figure>
]

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.box-5.large[Smoking → Cardiac arrest example]

???

| Person | Smoker | Cardiac arrest | Cholesterol | Weight | Lifestyle healthiness |
|--------|--------|----------------|-------------|--------|-----------------------|
| 1      | TRUE   | TRUE           | 150         | 170    | 6                     |
| 2      | TRUE   | FALSE          | 170         | 180    | 3                     |
| 3      | FALSE  | FALSE          | 130         | 110    | 9                     |
| 4      | FALSE  | TRUE           | 140         | 140    | 8                     |
| 5      | TRUE   | TRUE           | 120         | 150    | 2                     |
| 6      | TRUE   | FALSE          | 130         | 230    | 3                     |
| 7      | FALSE  | FALSE          | 140         | 250    | 10                    |

```text
dag {
bb="0,0,1,1"
"Cardiac arrest" [outcome,pos="0.599,0.432"]
Cholesterol [pos="0.415,0.440"]
Lifestyle [pos="0.156,0.317"]
Smoking [exposure,pos="0.243,0.428"]
Weight [adjusted,pos="0.297,0.255"]
Cholesterol -> "Cardiac arrest"
Lifestyle -> Smoking
Lifestyle -> Weight
Smoking -> Cholesterol
Weight -> Cholesterol
}
```

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.box-5.medium[How can you be sure you include everything in a DAG?]

.box-5.medium[Is there a rule of thumb for the number of nodes?]

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.box-5.medium[Why do DAGs have to be acyclic?]

.box-5.medium[What if there really is reverse causation?]

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.box-5.large[How do we actually adjust for these things?]

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.box-5.large[What's the difference between logic models and DAGs?]

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# DAGs vs. Logic models

.box-5.large[DAGs are a *statistical* tool]

.box-5.large.sp-before[Logic models are a *managerial* tool]

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???

https://twitter.com/andrewheiss/status/1208836534285340673

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.pull-left[
<figure>
 <img src="img/04-class/greenspace-eater.png" alt="Green space in Berkeley" title="Green space in Berkeley" width="100%">
</figure>
]

.pull-right[
<figure>
 <img src="img/04-class/greenspace-conversation.png" alt="Covid green spaces" title="Covid green spaces" width="100%">
</figure>
]

???

<https://theconversation.com/how-cities-can-add-accessible-green-space-in-a-post-coronavirus-world-139194>

<https://sf.eater.com/2020/5/14/21258980/berkeley-coronavirus-covid-19-jesse-arreguin-street-closures>