Noah Greifer
@noahgreifer.bsky.social
Statistical consultant and programmer at Harvard IQSS. Author/maintainer of the #Rstats packages 'MatchIt', 'WeightIt', and 'cobalt' for causal inference, among many others | He/him
ngreifer.github.io
ngreifer.github.io
Pinned
Noah Greifer
@noahgreifer.bsky.social
· Oct 31
So grateful for the new followers! I'll definitely be posting more on here, especially about #Rstats, causal inference, R package development, and my statistical interests more generally. Also happy to answer questions about any of the above. Feel free to tag me in stuff!
What do you mean my Bayesian logistic regression on a moderate sample took 3 minutes to run
November 4, 2025 at 4:41 PM
What do you mean my Bayesian logistic regression on a moderate sample took 3 minutes to run
Reposted by Noah Greifer
We 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?
October 27, 2025 at 5:39 PM
We 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?
Reposted by Noah Greifer
For 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/2510.07076
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/2510.07076
Confidence Regions for Multiple Outcomes, Effect Modifiers, and Other Multiple Comparisons
In 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...
arxiv.org
October 9, 2025 at 3:34 PM
For 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/2510.07076
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/2510.07076
My hot take is that "fixed effects" has a single, clear meaning that is equivalent across all subdisciplines of statistics.
October 5, 2025 at 12:44 AM
My hot take is that "fixed effects" has a single, clear meaning that is equivalent across all subdisciplines of statistics.
A 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 #casualsky
#statssky #casualsky
The Effects of a Place-Based Intervention on Resident Reporting of Crime and Service Needs: A Frontier Matching Approach
Prior 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...
doi.org
September 18, 2025 at 3:23 PM
A 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 #casualsky
#statssky #casualsky
Reposted by Noah Greifer
opossum my possum
February 14, 2025 at 5:02 PM
opossum my possum
I 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/
In short, {optweight} uses optimization to estimate balancing weights in observational studies.
#episky #statssky #causalsky
1/
Optimization-Based Stable Balancing Weights
Use 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>...
ngreifer.github.io
September 9, 2025 at 2:31 PM
I 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/
In short, {optweight} uses optimization to estimate balancing weights in observational studies.
#episky #statssky #causalsky
1/
Reposted by Noah Greifer
I 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
I present:
OUR BLESSED mixed models // THEIR BARBAROUS fixed effects
September 9, 2025 at 1:49 PM
I 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
I present:
OUR BLESSED mixed models // THEIR BARBAROUS fixed effects
Reposted by Noah Greifer
I'm teaching this workshop in two weeks! It's going to be great!
Looking 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.
Causal Inference in R | Online Workshop | Statistical Horizons
This online seminar taught by Noah Greifer, Ph.D., will introduce using the MatchIt and WeightIt packages in R for causal inference.
statisticalhorizons.com
July 29, 2025 at 1:52 PM
I'm teaching this workshop in two weeks! It's going to be great!
These course notes on nonparametric regression (including kernel density estimation) by Eduardo García Portugués are *fantastic*. So clear, with great visuals and clear code.
Chapter 6 Nonparametric regression | Notes for Predictive Modeling
<p>Notes for Predictive Modeling. MSc in Big Data Analytics.
Carlos III University of Madrid.</p>
bookdown.org
July 22, 2025 at 9:10 PM
These course notes on nonparametric regression (including kernel density estimation) by Eduardo García Portugués are *fantastic*. So clear, with great visuals and clear code.
Reposted by Noah Greifer
Looking 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.
Causal Inference in R | Online Workshop | Statistical Horizons
This online seminar taught by Noah Greifer, Ph.D., will introduce using the MatchIt and WeightIt packages in R for causal inference.
statisticalhorizons.com
July 22, 2025 at 1:14 PM
Looking 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.
A 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).
Relaxing Assumptions, Improving Inference: Integrating Machine Learning and the Linear Regression | American Political Science Review | Cambridge Core
Relaxing Assumptions, Improving Inference: Integrating Machine Learning and the Linear Regression - Volume 117 Issue 3
doi.org
July 16, 2025 at 8:40 PM
A 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).
Version 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().
{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().
Fractional Weighted Bootstrap
An 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...
ngreifer.github.io
July 9, 2025 at 3:58 PM
Version 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().
{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().
Randomly obsessed with simultaneous (uniform) inference. Feel free to ask about it. A mini thread on this follows. 🧵
Recommended reading:
#statssky #econsky #episky
Recommended reading:
#statssky #econsky #episky
Simultaneous confidence bands: Theory, implementation, and an application to SVARs
Simultaneous 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...
doi.org
July 3, 2025 at 9:20 PM
Reposted by Noah Greifer
An 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.
June 25, 2025 at 4:09 PM
An 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.
Reposted by Noah Greifer
Begging you to rank Zohran Mamdani for NYC mayor, and please DO NOT rank Cuomo.
June 20, 2025 at 8:21 PM
Begging you to rank Zohran Mamdani for NYC mayor, and please DO NOT rank Cuomo.
You know I had something to say.
Do 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
stats.stackexchange.com
June 24, 2025 at 2:06 PM
You know I had something to say.
Reposted by Noah Greifer
Bayesian Additive Regression Trees are fucking cool.
June 23, 2025 at 11:03 PM
Bayesian Additive Regression Trees are fucking cool.
Reposted by Noah Greifer
about that: www.sciencedirect.com/science/arti...
Is the “well-defined intervention assumption” politically conservative?
www.sciencedirect.com
June 20, 2025 at 1:32 PM
about that: www.sciencedirect.com/science/arti...
Begging you to rank Zohran Mamdani for NYC mayor, and please DO NOT rank Cuomo.
June 20, 2025 at 8:21 PM
Begging you to rank Zohran Mamdani for NYC mayor, and please DO NOT rank Cuomo.
Reposted by Noah Greifer
I'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!
June 14, 2025 at 2:08 PM
I'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!
Good 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!
Starting 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! 😅
June 12, 2025 at 6:00 PM
Good 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!