P-Hacking and Causal Modeling, a Forewarning
P-Hacking
John Oliver has a great episode called "Scientific Studies: Last Week Tonight with John Oliver (HBO)" that covers p-hacking. Google AI Search Labs gives a nice summary of p-hacking as follows: "
P-hacking is a statistical practice that involves manipulating data to produce a desired p-value. It's also known as data dredging or data snooping. P-hacking can lead to the publication of false positive results.
Here are some examples of p-hacking:
Selective reporting: Only reporting results that support a hypothesis, while ignoring those that don't
Multiple comparisons: Conducting multiple comparisons on the same data set without adjusting for them
Excluding participants: Excluding certain participants from the study
P-hacking can be difficult to detect because the results can be indistinguishable from genuine studies. However, some tips for avoiding p-hacking include:
Establishing hypotheses and sample sizes before collecting data
Avoiding testing for significance multiple times on the same data set
Not choosing a subset of data to analyze after observing the results
To prevent p-hacking, researchers can pre-register all the relevant details of their intended analysis, including the script they plan to use. They can do this using a site like OSF.
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Causal Modeling
Causal modeling is when you have a hypothesis and you try to prove that hypothesis with data, more specifically trying to find evidence of a causal relationship. Things that fall under the heading of causal modeling include:
A/B Testing
Propensity Score Matching
Exactly Matching
Counterfactual Causal Inference
Etc.
Forewarning
When doing causal modeling, sometimes we don't get the answer we're looking for, and so we try again. And again. And again. And eventually, we can find ourselves p-hacking or data dredging.
I think it's important to remember this caveat of causal modeling as we use these techniques. It can be a slippery slope, and it's always good to evaluate your approaches and assumptions as you move forward.
The End
Happy Learning everyone! :)











