Matching in Python: a balanced covariate table doesn't make the estimate valid
A propensity-score match can pass every balance check and still return the wrong number. Observed-covariate balance does not establish that a comparable control existed.
Jul 2026
Applied Econometrics
Reproducibility
Causal Inference
Synthetic control in Python: read the pre-fit before the gap
A zero-error pre-treatment fit returns a clean gap of 6.1 against a planted effect of 6.0, and the same zero-error fit returns a wrong gap of 4.3 when no valid counterfactual exists. Pre-treatment fit quality determines whether the post-treatment gap is interpretable.
Jul 2026
applied-econometrics
causal-inference
python
Regression discontinuity in Python: getting the effect at the cutoff right
A global polynomial fit returns a clean, plausible 1.8 where the effect planted at the cutoff is 0.75. A local fit recovers about 0.75. The article explains regression discontinuity in Python and a confounder that the local fit does not adjust for.
Jul 2026
applied-econometrics
causal-inference
python
How to tell whether a double machine learning estimate is right
Double machine learning in Python: why a naive plug-in estimates 0.55 when the true effect is 1.0, how cross-fitting recovers 0.97, and the confounder it still cannot detect.
Jul 2026
applied-econometrics
causal-inference
python
Using difference-in-differences in practice
When difference-in-differences fits, which assumptions matter, and how the design assumptions fail, shown across worked cases with study-level material status. A decision table maps each situation to the estimator and the corresponding diagnostic requirement.
Jul 2026
applied-econometrics
causal-inference
difference-in-differences
Instrumental Variables in Python: Strength Is Not Validity
The Mroz walkthrough reports OLS at 0.1075 and IV at 0.0614. A first-stage F of 55.4 supports relevance only; it cannot establish the independence or exclusion arguments required for a causal interpretation.
Jul 2026
applied-econometrics
causal-inference
python
Rolling DiD with Few Units: Article-Reported Simulation
An instructional guide to transformation choice and small-sample inference. The simulation estimates and Python rebuild are article-reported and not publicly reproduced.
Jun 2026
ai-workflow
applied-econometrics
causal-inference
AI Econometrics: Using AI for Code, Not for Identification
A conceptual division of labor for AI-assisted econometrics. The exact outputs in its worked examples are article-reported and not publicly reproduced.
Jun 2026
ai-workflow
applied-econometrics
causal-inference
How do we know an AI's estimator does what we meant?
Rebuilding an estimator from a paper or package, the code can run without error and still be wrong. A routine that detects the mismatch: name the low-visibility choices in a spec, plant a known truth in a simulation, and read the code against its source.
Jun 2026
applied-econometrics
reproducibility
ai-workflow
Comparing logistic regression with language-model readouts for survey prediction
The article reports a local model comparison. Its scripts, data provenance, saved outputs, and run record are not public, so the exact rankings and metrics are not independently reproduced.
Jun 2026
ai-workflow
applied-econometrics
machine-learning
A regression view of steering vectors
The article reports a local estimator experiment. Its scripts, construction corpus, saved outputs, and run record are not public, so the numerical comparison is not independently reproduced.
Jun 2026
ai-workflow
applied-econometrics
machine-learning
Prediction-powered inference for AI-assisted survey estimation
The article teaches the estimator through a local HINTS imputation example and a separate simulation. Neither has a public script, data-provenance record, saved output, or run record.
Jun 2026
ai-workflow
applied-econometrics
machine-learning
Well-Executed but Not Important
The article classifies 2,493 published health-economics abstracts by contribution scope. Identification and Reframing labels are associated with fitted 1.91x and 2.26x differences on the citations-plus-one geometric scale relative to Calibration; the selected sample does not identify editorial importance or a causal effect.
May 2026
meta-research
llm-classification
citations
Cycling Through Bad Ideas Faster: An Article-Reported Medicaid Example
An iterative-critique workflow built around Medicaid branding estimates and elapsed-time comparisons that are not publicly reproduced.
May 2026
medicaid
difference-in-differences
ai-workflow
Claude Code Skills Get Stale. Audit Them Quarterly.
A repeatable audit for skills, hooks, and memory entries created for older models before they shape current analysis.
May 2026
tutorial
claude-code
A pre-analysis plan for a coding agent
A three-layer architecture, rule, gate, and verification, for constraining reasoning-agent behavior when system prompts alone are not enough.
May 2026
tutorial
agents
Building a Literature Surveillance System
Combining Google Scholar and Semantic Scholar sources with an AI assistant that integrates citation networks and detects reference errors.
April 2026
tutorial
literature review
One Context File: A Workflow for Persistent Project Context
A teaching workflow for documenting project conventions in CLAUDE.md. Its session times, prevented-error counts, and savings estimates are not independently timed.
October 2025
tutorial
claude-md
Methods-to-Code with AI: An Article-Reported Workflow
A precise methods paragraph serves as an implementation specification. The transit example and timing comparison are article-reported and not publicly reproduced.
October 2025
tutorial
workflow
Cleaning a Research Codebase: An Article-Reported Example
A teaching workflow for mapping dependencies and reorganizing code. The script counts, changed imports, hashes, and timing claims are not publicly reproduced.
November 2025
tutorial
refactoring
Robust API Collection: Pagination, Rate Limits, Failure Recovery
The collection safeguards are documented. The article-reported record total, cost, retry log, and zero-loss claim remain under reconciliation.
November 2025
tutorial
api
Grocery Store Classifier Results Under Review
The article reports an iterative labeling result. Its full-population classification remains under reconciliation with the related policy pages.
October 2025
tutorial
validation
The Retail Density Paradox: Why More Stores Mean Worse Data
Cross-validating SNAP retailer data against multiple authoritative sources documents provenance for each label.
October 2025
tutorial
validation
Build Transit Travel-Time Matrices with Free Tools
Step-by-step guide to r5py, GTFS data, and multimodal accessibility analysis. The project-specific pair count is under reconciliation.
November 2025
tutorial
r5py
GTFS