Noah Greifer @noahgreifer.bsky.social · 18/09/2026BART is really nice for a frequentist who doesn't like priors because the BART priors are so far removed from the estimand posterior that it doesn't feel like you're prior-ing yourself into a finding. Also the default priors are sensible. So you get a flexible model with a posterior almost for free. 3100
Noah Greifer @noahgreifer.bsky.social · 17/09/2026Let's say I have a discrete 1-5 scale, and I want to model it with ordinal regression. Normally, this would involve estimating 4 threshold parameters. Let's say no one selects option 2. Should I retain the empty category and estimate its upper threshold? Or collapse to 4 levels w/ 3 thresholds? 552
Noah Greifer @noahgreifer.bsky.social · 03/08/2026I'm so happy to announce version 2.0.0 of my #Rstats package WeightIt is out on CRAN! New features: censoring weights, multilevel propensity scores, improved weights for continuous treatments, bias-reduced ordinal and multinomial models, M-estimation in subgroups Check out the website below!ngreifer.github.ioWeighting for Covariate Balance in Observational StudiesGenerates balancing weights for causal effect estimation in observational studies with binary, multi-category, or continuous point or longitudinal treatments by easing and extending the functionality ... 29037
Noah Greifer @noahgreifer.bsky.social · 03/08/2026Exciting new updates to #Rstats WeightIt coming soon... 👀 Any guesses? Here are two clues in emoji form: 1. 💀 2. 🏫 (Read separately! no death in schools please) 240
Noah Greifer @noahgreifer.bsky.social · 03/08/2026Fascinating and clear paper by @corymccartan.com and @melodyyhuang.bsky.social, greatly enhancing our understanding of how Bayesian Additive Regression Trees (BART) works and why it is so effective. A must-read for my fellow BART enthusiasts. #statssky #causalinference 13911
Noah Greifer @noahgreifer.bsky.social · 16/07/2026nursingclio.org/2026/07/15/s...nursingclio.orgSeductions of the Transparent Body: X-Rays, A.I. Body Scans, and CancerThere is no escaping cancer in the algorithm. In the months after finishing chemotherapy, targeted ads for A.I.-powered body scans filled my social media feed with stories about lurking malignancie… 010
Noah Greifer @noahgreifer.bsky.social · 29/06/2026This made me very happy to see :) www.nytimes.com/interactive/... 0742
Noah Greifer @noahgreifer.bsky.social · 02/06/2026New version of #Rstats {fwb} is out! {fwb} implements the fractional weighted bootstrap, aka the Bayesian bootstrap, which is an alternative to the traditional bootstrap that draws a set of weights for each bootstrap replication instead of sampling with replacement from the original sample.ngreifer.github.ioFractional Weighted BootstrapAn implementation of the fractional weighted bootstrap to be used as a drop-in for functions in the boot package. The fractional weighted bootstrap (also known as the Bayesian bootstrap) involves draw... 1386
Noah Greifer @noahgreifer.bsky.social · 01/05/2026This is the clearest and most accessible introduction to DML I've ever read: arxiv.org/abs/2504.08324 Congrats to the authors @aahrens.bsky.social, @markeschaffer.bsky.social, et al on this amazing paper and great accompanying R package! I'm now DML-pilled.arxiv.orgAn Introduction to Double/Debiased Machine LearningThis paper provides an introduction to Double/Debiased Machine Learning (DML). DML is a general approach to performing inference about a target parameter in the presence of nuisance functions: objects... 24813
Noah Greifer @noahgreifer.bsky.social · 22/04/2026This is a must-read by two of my research idols! 1200
Noah Greifer @noahgreifer.bsky.social · 10/04/2026arg! I wish R packages had better error messages! Now they can, thanks to my newest #Rstats package, {arg}! 😉 {arg} produces clean, simple, error messages for checking function arguments, similar to {checkmate}, {dreamerr}, and {chk}, using {cli} formatting.ngreifer.github.ioClean and Simple Argument CheckingChecks function arguments, ideally for use in R packages. Uses a simple interface and produces clean, informative error messages using cli. 56613
Noah Greifer @noahgreifer.bsky.social · 07/04/2026I'm teaching this 3-day seminar on matching and weighting in R next week! I'd love to see you there! 1172
Reposted by Noah GreiferMichael Wiebe @michaelwiebe.bsky.social · 13/03/2026🚨Replication alert🚨 I'm pleased to announce that my replication of Moretti (2021) is now accepted as a comment at AER. I find ten issues in the paper. My comment focuses on two major problems; in the appendix, I document eight (relatively) minor problems. 1/ 914950
Noah Greifer @noahgreifer.bsky.social · 04/03/2026But what if... I were to purchase propensity scores and disguise them as my own randomized trial? Delightfully devilish Seymour!media.tenor.coma cartoon character is looking out a window at krusty krabbsALT: a cartoon character is looking out a window at krusty krabbs 290
Noah Greifer @noahgreifer.bsky.social · 18/02/2026Some more details on the omnibus test for whether the ADRF is flat, as I mention in this test. We have an estimate for the ADRF at each treatment value `a`, and jointly they have a multivariate normal distribution. This makes the ADRF estimate a Gaussian Process. 1/8 132
Noah Greifer @noahgreifer.bsky.social · 18/02/2026I'm so excited to announce the first release of my newest #Rstats package, {adrftools}! This package facilitates estimation, visualization, and testing for the causal effect of a continuous (i.e., non-discrete) treatment. 🧵 1/10 #statssky #episky #causalinferencecran.r-project.orgadrftools: Estimating, Visualizing, and Testing Average Dose-Response FunctionsFacilitates estimating, visualizing, and testing average dose-response functions (ADRFs) for characterizing the causal effect of a continuous (i.e., non-discrete) treatment or exposure. Includes suppo... 511530
Noah Greifer @noahgreifer.bsky.social · 14/01/2026Bringing this back now that @marcratkovic.bsky.social is on Bluesky! 080
Reposted by Noah GreiferAndrew Heiss @andrew.heiss.phd · 09/12/2025Some closing thoughts for my students this semester on LLMs and learning #rstats datavizf25.classes.andrewheiss.com/news/2025-12... 14336103
Noah Greifer @noahgreifer.bsky.social · 13/11/2025Any #rstats advice for writing mathematical expressions in ggplot2 axis labels? Dying not to have to use the insanity that is bquote() 172
Noah Greifer @noahgreifer.bsky.social · 04/11/2025What do you mean my Bayesian logistic regression on a moderate sample took 3 minutes to run 8170
Reposted by Noah GreiferDan Lewer @danlewer.bsky.social · 27/10/2025We wrote an article explaining why you shouldn't put several variables into a regression model and report which are statistically significant - even as exploratory research. bmjmedicine.bmj.com/content/4/1/.... How did we do? 26275107
Reposted by Noah GreiferPausal Zivference @pausalz.bsky.social · 09/10/2025For years I had trouble following some of the discussion about confidence bands, but at ACIC this year @noahgreifer.bsky.social pointed me to a helpful paper So you don't have to be as perplexed as I once was, we have a new pre-print introducing the key ideas arxiv.org/abs/2510.07076arxiv.orgConfidence Regions for Multiple Outcomes, Effect Modifiers, and Other Multiple ComparisonsIn epidemiology, some have argued that multiple comparison corrections are not necessary as there is rarely interest in the universal null hypothesis. From a parameter estimation perspective, epidemio... 1208
Noah Greifer @noahgreifer.bsky.social · 05/10/2025My hot take is that "fixed effects" has a single, clear meaning that is equivalent across all subdisciplines of statistics. 280
Noah Greifer @noahgreifer.bsky.social · 18/09/2025A new paper I worked on is out in Justice Quarterly! I won't speak on the substantive nature of the paper as I worked solely as the methodologist, but I developed a new matching method not otherwise described in the literature, and I want to tell you about it! #statssky #casualskydoi.orgThe Effects of a Place-Based Intervention on Resident Reporting of Crime and Service Needs: A Frontier Matching ApproachPrior research has found that reporting of crime incidents and service needs remain low in many U.S. cities. This study employs a matching strategy using observational data from a large public repo... 2275
Noah Greifer @noahgreifer.bsky.social · 09/09/2025I recently updated my #Rstats package {optweight} for the first time in 6 years(!), and I want to give it the attention it deserves with an announcement and mini thread. In short, {optweight} uses optimization to estimate balancing weights in observational studies. #episky #statssky #causalsky 1/ngreifer.github.ioOptimization-Based Stable Balancing WeightsUse optimization to estimate weights that balance covariates for binary, multi-category, continuous, and multivariate treatments in the spirit of Zubizarreta (2015) <doi:10.1080/01621459.2015.1023805>... 2315
Reposted by Noah GreiferCameron Patrick @cameronpat.bsky.social · 09/09/2025I could have sworn I created this before on our Previous Parish, but couldn't find it so made it fresh. I present: OUR BLESSED mixed models // THEIR BARBAROUS fixed effects 410124
Noah Greifer @noahgreifer.bsky.social · 29/07/2025I'm teaching this workshop in two weeks! It's going to be great! 051
Noah Greifer @noahgreifer.bsky.social · 22/07/2025These course notes on nonparametric regression (including kernel density estimation) by Eduardo García Portugués are *fantastic*. So clear, with great visuals and clear code.bookdown.orgChapter 6 Nonparametric regression | Notes for Predictive Modeling<p>Notes for Predictive Modeling. MSc in Big Data Analytics. Carlos III University of Madrid.</p> 4535
Reposted by Noah GreiferStatistical Horizons @stathorizons.bsky.social · 22/07/2025Looking to strengthen your #causalinference skills? Join @noahgreifer.bsky.social on Aug. 12-15 for "Causal Inference in R Using MatchIt and WeightIt" to gain the skills to apply these #Rstats packages to estimate and interpret treatment effects.statisticalhorizons.comCausal Inference in R | Online Workshop | Statistical HorizonsThis online seminar taught by Noah Greifer, Ph.D., will introduce using the MatchIt and WeightIt packages in R for causal inference. 043
Noah Greifer @noahgreifer.bsky.social · 16/07/2025A nice paper by Mark Ratkovic on double machine learning (DML) oriented toward political scientists, with some advancements to accommodate interference and clustering. Definitely a worthwhile read, especially if the foundational papers on this topic intimidate you (as they do me).doi.orgRelaxing Assumptions, Improving Inference: Integrating Machine Learning and the Linear Regression | American Political Science Review | Cambridge CoreRelaxing Assumptions, Improving Inference: Integrating Machine Learning and the Linear Regression - Volume 117 Issue 3 2272
Noah Greifer @noahgreifer.bsky.social · 09/07/2025A nice recent article on why you should abandon hazard ratios. #statssky #episkydoi.orgHow hazard ratios can mislead and why it matters in practice - European Journal of EpidemiologyHazard ratios are routinely reported as effect measures in clinical trials and observational studies. However, many methodological works have raised concerns about the interpretation of hazard ratios ... 27920
Noah Greifer @noahgreifer.bsky.social · 09/07/2025Version 0.5.0 of #Rstats {fwb} is out! {fwb} implements the fractional weighted bootstrap (aka Bayesian bootstrap), which involves repeatedly sampling sets of weights and computing the quantity of interest in each weighted sample. It contains drop-ins for boot::boot() and sandwich::vcovBS().ngreifer.github.ioFractional Weighted BootstrapAn implementation of the fractional weighted bootstrap to be used as a drop-in for functions in the boot package. The fractional weighted bootstrap (also known as the Bayesian bootstrap) involves draw... 2194
Noah Greifer @noahgreifer.bsky.social · 03/07/2025Randomly obsessed with simultaneous (uniform) inference. Feel free to ask about it. A mini thread on this follows. 🧵 Recommended reading: #statssky #econsky #episkydoi.orgSimultaneous confidence bands: Theory, implementation, and an application to SVARsSimultaneous confidence bands are versatile tools for visualizing estimation uncertainty for parameter vectors, such as impulse response functions. In linear models, it is known that that the sup-t c... 1439
Reposted by Noah GreiferSimon Columbus @simoncolumbus.bsky.social · 25/06/2025An idea for expedited reviews: Show me your abstract and I'll send you the @dingdingpeng.the100.ci paper you should've read before you started your project. 1213
Reposted by Noah GreiferNoah Greifer @noahgreifer.bsky.social · 20/06/2025Begging you to rank Zohran Mamdani for NYC mayor, and please DO NOT rank Cuomo. 151
Noah Greifer @noahgreifer.bsky.social · 24/06/2025You know I had something to say.stats.stackexchange.comDo you still need matching in IWP/double robust methods?In inverse probability weighting (IWP) and double robust (DR) methods, each observation is given a weight proportional to receiving the treatment and this serves to balance covariate distributions 2152
Reposted by Noah GreiferJordan Nafa @ajordannafa.com · 24/06/2025Bayesian Additive Regression Trees are fucking cool. 2151
Reposted by Noah GreiferHerb Susmann @herbps10.bsky.social · 20/06/2025about that: www.sciencedirect.com/science/arti...sciencedirect.comIs the “well-defined intervention assumption” politically conservative? 053
Noah Greifer @noahgreifer.bsky.social · 20/06/2025Begging you to rank Zohran Mamdani for NYC mayor, and please DO NOT rank Cuomo. 151
Reposted by Noah GreiferStephen Vaisey 🇺🇦 @stephenvaisey.com · 14/06/2025I'm trying to find someone to teach a short course helping SAS users (specifically) transition to #Rstats. If you are such a person or are willing to recommend someone, my DMs are open! 4106
Noah Greifer @noahgreifer.bsky.social · 12/06/2025Good news, Harvard renewed my contract (for 6 months) so I remain employed and will continue to do my best to write great R packages and support applied research for Harvard and MIT affiliates :) Thank you so much for the support in a vulnerable moment! 7723
Reposted by Noah GreiferKyle Butts @kylefbutts.bsky.social · 08/06/2025github.com/kylebutts/vs... If you are using vscode and stata, you should try out my extension. It uses interactive window which let's you write in a `.do` file but get a notebook type experience. 14816
Noah Greifer @noahgreifer.bsky.social · 04/06/2025Starting to look like I might not be able to work at Harvard anymore due to recent funding cuts. If you know of any open statistical consulting positions that support remote work or are NYC-based, please reach out! 😅 1115296
Reposted by Noah GreiferAndrew Heiss @andrew.heiss.phd · 03/06/2025In October I'll be giving a 2-day workshop at @stathorizons.bsky.social about how to make beautiful websites with #QuartoPub! Learn how to make and deploy personal websites, research websites, an course websites all with minimal HTML/CSScodehorizons.comQuarto Websites | Online Seminar | Code HorizonsThis online course taught by Andrew Heiss, Ph.D., teaches you how to use Quarto to build a variety of data-focused websites. 14312
Reposted by Noah GreiferLucy D’Agostino McGowan @lucystats.bsky.social · 03/06/2025📣 July 22-25 I’ll be teaching an online short course on how to read and understand statistics commonly found in medical literature — tell your clinician friends! @stathorizons.bsky.social statisticalhorizons.com/seminars/und...statisticalhorizons.comUnderstanding Statistics in Medical Literature SeminarThis online workshop by Lucy D’Agostino McGowan introduces the core concepts of data and statistics, equipping you with the tools to extract meaningful insights from research. 02812