Zachary Fisher

adrftools: Estimating, Visualizing, and Testing Average Dose-Response Functions Facilitates 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...

I'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.

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#statssky #episky #causalinference

Researchers often treat ordinal variables as continuous. What if we could mimic this in an ordinal factor analysis/IRT model? We propose new identification constraints so that the latent variable goes from 1 to (# of ordered categories), with connections to treating ordinal variables as continuous.

Foundations of Item Response Theory This workshop from Wes Bonifay focuses on the foundations and application of item response theory, particularly as applied to binary items.

Enroll in my new workshop to realize your dream of learning IRT

#quantpsych #psychometrics #psychsky #statssky

#rstats
It is with profound sadness I heard that my long-time friend and colleague, John Fox passed away this week.
He was the author of {car}, {effects}, {Rcmdr}, ... and numerous influential books. I will miss him greatly.
www.john-fox.ca

Meeting the Bare Minimum: Quality Assessment of Idiographic Temporal Networks Using Power Analysis and Predictive-Accuracy Analysis - Yong Zhang, Jordan Revol, Ginette Lafit, Anja F. Ernst, Josip Razu... The network theory of psychopathology inspired clinicians and researchers to use idiographic networks to study how symptoms of an individual interact over time,...

From my master’s thesis to my first PhD project — excited to share that this work (together with @jordanrvl.bsky.social, @ginettelafit.bsky.social, Anja Franziska Ernst, Josip Razum, Eva Ceulemans, and @bringmannlaura.bsky.social) is now published in AMPPS!

Link: doi.org/10.1177/2515...

A new publication from my PhD project on model selection for nonstationary time-series data is out, co-authored with an amazing team (Anja Franziska Ernst, @ginettelafit.bsky.social , Ward B. Eiling, @bringmannlaura.bsky.social)!

Link: doi.org/10.1111/bmsp...

We’re hiring in Quantitative Psychology at UNC Chapel Hill!

Feel free to reach out if you have any questions about the program and please share widely!

unc.peopleadmin.com/postings/307...

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UNC is hiring in Quantitative Psychology! Assistant Professor (tenure-track). Please share widely! Find details here: unc.peopleadmin.com/postings/307...

Wanted to announce that I will be recruiting graduate students this year in Quantitative Psychology here at UC Davis. If you are or know of any undergrads who are interested in dynamical systems and network analytic methods, please send them my way or get in touch!

We’re hiring in Quantitative Psychology at UNC Chapel Hill!

Feel free to reach out if you have any questions about the program and please share widely!

unc.peopleadmin.com/postings/307...

A new semester is upon us! This time, I’m teaching Structural Equation Modeling. Want to follow along? Here you go: jonathantemplin.github.io/Structural-E... and www.youtube.com/playlist?lis... #StatModeling #SEM

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Trigonometric functions and a unit circle

A bivariate change model with structured residuals

A hierarchical model of cognitive abilities

Now on CRAN, ggdiagram is a #ggplot2 extension that draws diagrams programmatically in #Rstats. Allows for precise control in how objects, labels, and equations are placed in relation to each other.
wjschne.github.io/ggdiagram/ar...

This work was officially accepted for publication today!

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! 😅

Postdoc position open in Zurich -- Prof. Martin Tomasik and I have a joint SNF project on interpretable neural network approaches for large scale, complex item / temporal structure, online learning / cognitive development data.

Please retweet.

tinyurl.com/PostdocGNNSNF

🚀 PhD Position in Psychological Methods at @unimarburg.bsky.social
📅 Start: 01.10.2025 | 💼 50% TV-H E13 | ⏳ 3 years

Focus on statistical modeling—Bayesian statistics, cognitive modeling, psychometrics.

🔗 Apply now: uni-marburg.de/r5dKTr

🔄 Thanks for sharing!

Antrittsvorlesung von Prof. Dr. Charles Driver Human Behaviour, Cognition and Emotions as Dynamic Systems

For anyone who'd like the verbal / visual introduction to my work in quant psych / dynamic systems (or a little of the personal background), I gave my inaugural lecture with UZH Monday night and it's available here: vimeo.com/showcase/826...

We’re hiring postdocs to join my lab at UNC. If you’re interested in adolescence, brain, and social development, DM me. Our work incorporates fMRI, social media, and longitudinal methods. We study risks and opportunities in adolescence. If you’re at #SRCD2025 and want to meet, please reach out!

Model to Meaning: How to interpret statistical models with marginaleffects for R and Python

📚😅🎉

Yay!! I just submitted the complete manuscript of my upcoming book to the publisher!

Learn to easily and clearly interpret (almost) any stats model w/ R or Python. Simple ideas, consistent workflow, powerful tools, detailed case studies.

Read it for free @ marginaleffects.com

#RStats #PyData

This paper on intensive longitudinal reliability led by Sebastian Castro-Alvarez is one of the best I've read in a while -- the review was so thorough, the code was fantastic, and it answered any questions I had about IL reliability. Definitely check it out you work with ILD!

osf.io/preprints/ps...

LatentGOLD 6.1 Academic New License - Statistical Innovations LG 5.1 Academic Latent GOLD new license LG Choice Advanced Syntax Latent Class Discrete Choice 3step markov multilevel scale factor 5.1 annual perpetual

🤓Latent GOLD licenses for academic use are now freely available on the website! www.statisticalinnovations.com/shop/lg-6-1-...

Unsupervised Model Construction in Continuous-Time Many of the advancements reconciling individual- and group-level results have occurred in the context of a discrete-time modeling framework. Discrete-time models are intuitive and offer relatively ...

My first paper as an Assistant Professor at UC Davis is out in the journal SEM!

In the paper, we introduce a continuous-time extension to the GIMME model implemented in OpenMx. It uses iterative tests of modification indices to construct group- and person-specific dynamic networks!

For the quant methods people in my circle:

Tenure-track Assistant Professor specializing in measurement and psychometric issues related to complex data structures.

Scientists don't have to be in academia to make a huge impact! Check out this new resource for details, salaries, etc on how to pick a career!
#psychology #PsychSky #mentalhealth #PsychSciSky #Skychiatry #Neuroskyence #neuroimaging
#PsychSciSky #CogPsyc #ClinPsych

www.apa.org/science/prog...

A Review of Some of the History of Factorial Invariance and Differential Item Functioning The concept of factorial invariance has evolved since it originated in the 1930s as a criterion for the usefulness of the multiple factor model; it has become a form of analysis supporting the vali...

This article gives a phenomenal overview of the history and evolution of best practices in measurement invariance and differential item functioning -- I can't remember the last time I learned so much reading a single paper, highly recommended!
www.tandfonline.com/doi/full/10....

Starter pack for EMA, ESM, and Intensive Longitudinal Researchers.

Feel free to share, follow, and nominate. Suggestions welcome!

go.bsky.app/LzqJoUX

#ESM #EMA #AA #IntensiveLongitudinalResearch

Penalized Subgrouping of Heterogeneous Time Series Interest in the study and analysis of dynamic processes in the social, behavioral, and health sciences has burgeoned in recent years due to the increased availability of intensive longitudinal...

We have a new preprint!

I'm excited to share recent work related to modeling multiple-subject, multivariate time series.

We extend the multi-VAR framework to allow for data-driven identification and penalized estimation of subgroup-specific dynamics.

arxiv.org/abs/2409.03085

We're hiring a tenure track Quantitative Psychologist at University of North Carolina - Chapel Hill!
We are particularly (but not exclusively) seeking someone with expertise in the measurement and modeling of high-density data structures.
unc.peopleadmin.com/postings/288222
Please share widely.

I made an attempt at a bsky psychometrics starter pack with people who work on or largely with psychometric tools! Please reskeet and (selfl!)nominate to help me fill my many and varied blind spots and make this a useful and balanced resource #rstats #psychometrics go.bsky.app/6oGLp7D