Peng Ding Profile
Peng Ding

@pengding00

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Associate Professor of Statistics

Berkeley
Joined December 2022
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@pengding00
Peng Ding
9 months
I just uploaded the R code and datasets to Harvard Dataverse: I plan to provide Python code as well but I need to learn Python first.
@CavaliereGiu
Giuseppe Cavaliere
9 months
Hi #EconTwitter ! Interested in exploring #statistics for 𝐂𝐚𝐮𝐬𝐚𝐥 𝐈𝐧𝐟𝐞𝐫𝐞𝐧𝐜𝐞? Don't miss👇the October 2023 edition of these outstanding undergrad notes by @pengding00 from @UCBStatistics . They are a great supplement to #econometrics books discussing difference in
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@pengding00
Peng Ding
1 year
My lecture notes on causal inference
@johnleibniz
Fang Han
1 year
Look at what I found on arXiv today 🤩 ⁦ @pengding00
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@pengding00
Peng Ding
6 months
I just posted my notes for Stat 230 ``Linear Models'' to ArXiv: It covers the linear model and many extensions. I will teach it again in the spring and continue polishing the notes. Comments are welcome.
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@pengding00
Peng Ding
8 months
Z-bias is mysterious. I learned the intuition from Robins: ``If we adjust for the instrumental variable, the treatment variation is driven more by the unmeasured confounder, which could result in increased bias due to this confounder...'' in Section 1.
@Apoorva__Lal
apoorva.lal
8 months
The inverse of this is also interesting: adjusting for covariates that only predict X (thereby reducing Var(X̃)) increases β, thereby producing bias (known as Z-bias - @pengding00 notes:). Think back to facile comments in seminars about "but have you controlled for <something>".
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@pengding00
Peng Ding
8 months
This is amazing. Python code for ``A first course in causal inference'': Thank you, Apoorva.
@Apoorva__Lal
apoorva.lal
8 months
Done with python code to accompany all chapters of @pengding00 's textbook. IV and matching are not well supported in python, so I might spin those out into a package eventually.
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@pengding00
Peng Ding
30 days
This is an interesting and useful trick. However, centering factors has some special restrictions on the estimated factorial effects when there are more than 3 factors (3 is the magic number there!). This motivates us to write this paper:
@matt_blackwell
Matt Blackwell
1 month
A fun fact about regression that many know but maybe is new to you: If you have an interaction bw continuous X1 and binary X2, mean-centering X1 will make the coefficient on X2 be its marginal effect when X1 is at its mean level rather than 0 without changing the interaction
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@pengding00
Peng Ding
28 days
IPW with the estimated propensity score is another example. The first-stage estimation reduces the asymptotic variance, which surprises many people. A recent paper is Also, Newey&McFadden chapter 6 is about "two-step estimation"
@Apoorva__Lal
apoorva.lal
29 days
Anyone have other examples of multi-step estimation problems where one needs to propagate uncertainty in first-step estimation into subsequent-stage coefficients? Generated regressors would be a standard example (eg centering regressors as in qt)
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@pengding00
Peng Ding
8 months
Dennis observed the numerical equivalence of the Horizontal and Vertical Regression in panel data @gitinmabellayo based on the OLS interpolator. Now we are interested in the OLS interpolator itself:
@CavaliereGiu
Giuseppe Cavaliere
8 months
Hi #EconTwitter ! 📈 Interested in causal inference based on panel data? Check out 👇this recent #econometrics paper (accepted in Econometrica) by Dennis Shen, Jasjeet Sekhon and @UCBerkeley statisticians @pengding00 & Bin Yu. They explore the merger of time series &
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@pengding00
Peng Ding
3 months
Hope we provide some new insights into the old problem of missing data in RCTs. @FanLiDuke
@FanLiDuke
Fan Li
3 months
Happy to see my paper with @pengding00 and Anqi Zhao @DukeU "Covariate adjustment in randomized experiments with missing outcomes and covariates" is out This 8-pages paper gives a simple and clean solution to a prevalent practical problem.
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@pengding00
Peng Ding
8 months
The bias-corrected matching estimator has the same form as the doubly robust estimator; see proposition 15.2 of Zhexiao and Fang made the argument rigorous! @zzzxlin @johnleibniz
@zzzxlin
Zhexiao Lin
8 months
🤩Finally come!!! Very fortunate to be advised by Fang @johnleibniz and Peng @pengding00 on this paper.
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@pengding00
Peng Ding
2 months
Fan Li's slides for causal inference
@FanLiDuke
Fan Li
2 months
Done another semester teaching causal inference🙂. Updated my course slides, added survival data, labs, corrected more typos this time. Close to 800 pages now. Always more to update next year.
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@pengding00
Peng Ding
4 months
``control'' means many different things in statistics, e.g. treatment-control experiment; control for confounding; case-control study; negative control; controlled direct effect; control function. ``control'' can even mean covariates (good or bad controls).
@RuiWang97
Rui Wang 王瑞
4 months
@pengding00 @carolcaetanoUGA May I ask what does “control” mean? I feel people usually just call it potential outcome. “Control” sounds like a mediation terminology.
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@pengding00
Peng Ding
30 days
@BhramarBioStat Totally agree. We are still teaching those classic topics at Berkeley.
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@pengding00
Peng Ding
29 days
@linstonwin @Apoorva__Lal @FelixThoemmes @matt_blackwell Also, the bootstrap is always a panacea to problems like this. But we need to center x in each bootstrap sample. If we center x before the bootstrap, we will get the EHW se again. I included this as a numerical exercise in Problem 9.2 of the book:
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@pengding00
Peng Ding
8 months
@jmwooldridge I used the phrase ``population residual'' in Appendix B of I remember that @stat110 did not like it when he read my early draft.
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@pengding00
Peng Ding
7 months
@AngYu_soci In theory (and intuitively), if you include more terms in the logit pscore model, you can get better efficiency and potentially achieve the efficiency bound.
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@pengding00
Peng Ding
8 months
@Yiqiao_Zhong @karlrohe I think Gauss showed more: for OLS to be optimal, the noise must be Gaussian. The other way is easier to show and it is a current textbook result.
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@pengding00
Peng Ding
4 months
@carolcaetanoUGA control potential outcome?
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@pengding00
Peng Ding
2 months
@yudapearl You can download the PDF of it from the UCLA library. I just download it from the UC Berkeley library.
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@pengding00
Peng Ding
2 months
@pedrohcgs This is too bad. I do not understand why some reviewers and editors want to waste everybody's time.
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@pengding00
Peng Ding
1 year
@BerkOzler12 Thanks for the nice summary of our paper.
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@pengding00
Peng Ding
8 months
@Apoorva__Lal Maybe you can try a simpler variance estimator in the first displayed formula on page 208 of It is equivalent to Otsu and Rai (2017)'s bootstrap variance estimator. But you do not need to bootstrap.
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@pengding00
Peng Ding
7 months
@Apoorva__Lal @johnleibniz @zzzxlin This seems a hard question in practice. Maybe the best way is to display a sequence of estimates and se's with varying M.
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@pengding00
Peng Ding
8 months
What is your intuition, @yudapearl ? You wrote the paper on Z-bias.
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@pengding00
Peng Ding
2 months
@qsunstats We used it for variance estimation because the in-sample residuals are 0: see section 5.3 of . .
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@pengding00
Peng Ding
8 months
@Apoorva__Lal @RobDonnelly47 I drew the DAGs for M-bias and Z-bias using \xymatrix -:) $$ \xymatrix{ U_1 \ar[dd]\ar[dr] &&U_2 \ar[dd]\ar[dl] \\ &X& \\ Z && Y } $$ and $$ \xymatrix{ &&&U \ar[dl]_b \ar[dr]^c \\ X \ar[rr]^a &&Z\ar[rr]^\tau && Y } $$
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