$npx -y skills add scdenney/open-science-skills --skill hypothesis-buildingBuild falsifiable causal hypotheses. Use for DAGs, FPCI, equivalence testing, mechanism specification, and deriving testable predictions from theory.
| 1 | # Causal Hypothesis Architect |
| 2 | |
| 3 | ## Instructions |
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| 5 | ### 1. The Identification Challenge |
| 6 | - **Verify FPCI Resolution:** Confirm that random assignment (or the identification strategy) solves the Fundamental Problem of Causal Inference for this design (Druckman 2022). |
| 7 | - **Three Prerequisites for Experiments:** Before proceeding, verify that the design meets the three prerequisites for causal inference from experiments: (1) *random assignment* to conditions, (2) *exclusion restriction* (the only difference between conditions is the treatment itself), and (3) *SUTVA* (the Stable Unit Treatment Value Assumption, i.e. noninterference -- one subject's treatment does not affect another's outcome) (Druckman 2022, following Gerber & Green 2012). |
| 8 | - **Define the Data Generating Process (DGP):** Before drafting the hypothesis, describe the set of rules that governs how the data is created. What are the underlying mechanics of the world being studied? |
| 9 | - **Map the Causal Diagram:** Where appropriate, draw a DAG. Identify backdoor paths and confirm whether randomization closes them (Mutz 2011). |
| 10 | - **Close the Backdoors:** State which variables must be controlled for to isolate the treatment effect. If using an experiment, explain how random assignment closes these paths (Mutz 2011). |
| 11 | - **SATE vs. PATE:** Distinguish between the Sample Average Treatment Effect (SATE) and the Population Average Treatment Effect (PATE). A convenience-sample experiment estimates a SATE; a population-based experiment on a representative sample estimates the PATE directly by design, without requiring statistical modeling or extrapolation (Mutz 2011; Druckman 2022). |
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| 13 | ### 2. Hypothesis Formulation |
| 14 | - **Popperian Falsifiability:** Frame the hypothesis as a "basic statement", or a specific observation that, if found to be false, would invalidate the theory. |
| 15 | - **The Counterfactual Logic:** Every hypothesis must specify a comparison. Define the "untreated" world. If the hypothesis is that X causes Y, what is the specific state of the world where X is absent? Note that in many survey experiments there may be no "pure control" -- each condition provides information, just different information (Druckman 2022). Distinguish between *active* control groups (which receive different information on the same topic, controlling for the act of receiving information) and *passive* control groups (no information), as this choice defines the counterfactual and thus the estimand (Stantcheva 2023). |
| 16 | - **Directional Clarity:** Avoid "existence" claims (e.g., "there is an effect"). Use "ordinal" claims that specify the direction (higher/lower) and, where possible, the expected functional form. |
| 17 | - **Beat Credible Competitors:** The goal of a hypothesis test is not merely to reject the null of "no effect" but to beat credible alternative explanations. Design experiments that adjudicate between competing theories -- "the point of the experiment is explication, not demonstration" (Sniderman 2018). A hypothesis is stronger when it specifies which competing theoretical account would be undermined by the predicted result. |
| 18 | - **Null-by-Design Thinking:** If the theory predicts no effect below a threshold of treatment intensity, specify (a) the intensity threshold, (b) expert-panel review of treatment strength before fielding, and (c) the equivalence bounds for the statistical test. Route such designs to the equivalence test in §3 (Sniderman 2018). |
| 19 | - **Estimand Specification:** Every hypothesis must map to a specific estimand -- the statistical quantity that, if estimated, would test the hypothesis. State the *theoretical estimand* (the target quantity, defined outside any statistical model) before choosing the *empirical estimand* (a function of observable data) and the estimation strategy; each step requires different assumptions and should be argued separately (Lundberg, Johnson, & Stewart 2021). For experimental designs, this typically means specifying: (a) the treatment contrast (what is compared to what), (b) the outcome metric (probability, scale score, etc.), and (c) the model that produces the estimate (e.g., AMCE from a conjoint, ATE from a vignette experiment). A hypothesis without a named estimand is not pre-registrable. Where feasible, declare the design formally using the MIDA framework -- model, inquiry, data strategy, answer strategy -- so that power, bias, and estimator--estimand coherence can be diagnosed computationally before fielding (Blair, Cooper, Coppock, & Humphreys 2019). For information/pedagogical experiments, distinguish between *first-stage* estimands (the belief or knowledge the treatment shifts) and *second-stage* estimands (the policy views influenced by those beliefs), with the causal chain explicit (Stantcheva 2023). |
| 20 | - **Information Equivalence:** In survey e |