Maarten Marsman
@maartenmarsman.bsky.social
690 followers 140 following 17 posts
Assistant Professor at the University of Amsterdam
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maartenmarsman.bsky.social
🚀 bgms 0.1.6.0 is now on CRAN!

New in this release:
• NUTS & HMC sampling for bgm() + bgmCompare()
• Parallel chains + reproducible runs via seed
• Markov chain diagnostics (ESS, R-hat)
• New summary(), print(), and coef() methods

🔗https://cran.r-project.org/web/packages/bgms/index.html
maartenmarsman.bsky.social
🚀 bgms 0.1.6.0 is now on CRAN!

New in this release:
• NUTS & HMC sampling for bgm() + bgmCompare()
• Parallel chains + reproducible runs via seed
• Markov chain diagnostics (ESS, R-hat)
• New summary(), print(), and coef() methods

🔗https://cran.r-project.org/web/packages/bgms/index.html
Reposted by Maarten Marsman
singmann.bsky.social
Exciting #rstats news for Bayesian model comparison: bridgesampling is finally ready to support cmdstanr, see screenshot. Help us by installing the development version of bridgesampling and letting us know if it works for your model(s): pak::pkg_install("quentingronau/bridgesampling#44")
R code and output showing the new functionality:
``` r
## pak::pkg_install("quentingronau/bridgesampling#44")
## see: https://cran.r-project.org/web/packages/bridgesampling/vignettes/bridgesampling_example_stan.html
library(bridgesampling)

### generate data ###
set.seed(12345)
mu <- 0
tau2 <- 0.5
sigma2 <- 1
n <- 20
theta <- rnorm(n, mu, sqrt(tau2))
y <- rnorm(n, theta, sqrt(sigma2))

### set prior parameters ###
mu0 <- 0
tau20 <- 1
alpha <- 1
beta <- 1

stancodeH0 <- 'data {
  int<lower=1> n; // number of observations
  vector[n] y; // observations
  real<lower=0> alpha;
  real<lower=0> beta;
  real<lower=0> sigma2;
}
parameters {
  real<lower=0> tau2; // group-level variance
  vector[n] theta; // participant effects
}
model {
  target += inv_gamma_lpdf(tau2 | alpha, beta);
  target += normal_lpdf(theta | 0, sqrt(tau2));
  target += normal_lpdf(y | theta, sqrt(sigma2));
}
'
tf <- withr::local_tempfile(fileext = ".stan")
writeLines(stancodeH0, tf)
mod <- cmdstanr::cmdstan_model(tf, quiet = TRUE, force_recompile = TRUE)

fitH0 <- mod$sample(
  data = list(y = y, n = n,
              alpha = alpha,
              beta = beta,
              sigma2 = sigma2),
  seed = 202,
  chains = 4,
  parallel_chains = 4,
  iter_warmup = 1000,
  iter_sampling = 50000,
  refresh = 0
)
#> Running MCMC with 4 parallel chains...
#> 
#> Chain 3 finished in 0.8 seconds.
#> Chain 2 finished in 0.8 seconds.
#> Chain 4 finished in 0.8 seconds.
#> Chain 1 finished in 1.1 seconds.
#> 
#> All 4 chains finished successfully.
#> Mean chain execution time: 0.9 seconds.
#> Total execution time: 1.2 seconds.
H0.bridge <- bridge_sampler(fitH0, silent = TRUE)
print(H0.bridge)
#> Bridge sampling estimate of the log marginal likelihood: -37.73301
#> Estimate obtained in 8 iteration(s) via method "normal".

#### Expected output:
## Bridge sampling estimate of the log marginal likelihood: -37.53183
## Estimate obtained in 5 iteration(s) via method "normal".
```
Reposted by Maarten Marsman
ninazeelen.bsky.social
De redactie verzweeg het feit dat de voorstellen van GL-Pvda volledig onderschreven wordt door het WRR-rapport Goede Zaken. Geen manipulatietechniek wordt geschuwd om de oppositie kapot te maken.
Reposted by Maarten Marsman
fbartos.bsky.social
Fair coins tend to land on the same side they started: evidence from 350,757 flips.

That's the title of our paper summarizing ~650 hours of coin-tossing experimentation just published in the Journal of the American Statistical Association.
doi.org/10.1080/0162...
Reposted by Maarten Marsman
clintin.bsky.social
New paper with @richarddmorey.bsky.social now out in JASA, where we critically examine p-curve. Below is Richard’s excellent summary of the many poor statistical properties of p-curve (with link to paper). I wanted to add some conceptual issues that we also tackle in the paper.
richarddmorey.bsky.social
Paper drop, for anyone interested in #metascience, #statistics, or #metaanalysis! @clintin.bsky.social and I show in a new paper in JASA that the P-curve, a popular forensic meta-analysis method, has deeply undesirable statistical properties. www.tandfonline.com/doi/full/10.... 1/?
Cover page for the manuscript: Morey, R. D., & Davis-Stober, C. P. (2025). On the poor statistical properties of the P-curve meta-analytic procedure. Journal of the American Statistical Association, 1–19. https://doi.org/10.1080/01621459.2025.2544397 Abstract for the paper: The P-curve (Simonsohn, Nelson, & Simmons, 2014; Simonsohn, Simmons, & Nelson, 2015) is a widely-used suite of meta-analytic tests advertised for detecting problems in sets of studies. They are based on nonparametric combinations of p values (e.g., Marden, 1985) across significant (p < .05) studies and are variously claimed to detect “evidential value”, “lack of evidential value”, and “left skew” in p values. We show that these tests do not have the properties ascribed to them. Moreover, they fail basic desiderata for tests, including admissibility and monotonicity. In light of these serious problems, we recommend against the use of the P-curve tests.
maartenmarsman.bsky.social
…we had a fantastic group of researchers. Participants dived in with curiosity, asking sharp questions, testing ideas, and applying new techniques to their own data.

And the coffee breaks came with this view. ☕🏞️
maartenmarsman.bsky.social
This week, I had the pleasure of teaching the Bayesian approach to network analysis at the Network Psychometrics summer school at Lake Como School of Advanced Studies.

Organized by Giulio Constantini, Michela Zambelli, and Semira Tagliabue with @briganti.bsky.social and @anastasiapsy.bsky.social
Reposted by Maarten Marsman
clbockting.bsky.social
Ben jij gedreven om psychische klachten te voorkomen voordat ze beginnen of terugkeren? Dan is dit promotietraject iets voor jou!

Shift Left @Arkin @amsterdamumc.bsky.social

lnkd.in/di4vWujy
@uvapsychology.bsky.social
LinkedIn
This link will take you to a page that’s not on LinkedIn
lnkd.in
maartenmarsman.bsky.social
"So EJ, say I am tossing a coin..."
Reposted by Maarten Marsman
jasp-services.com
Hello world! We are a new company that provides support for organizations and industries who use the JASP open-source stats program. Check out our website www.jasp-services.com and our first blog post www.jasp-services.com/first-post/
Know companies using commercial stats software? Share this info!🙂
Home - JASP Services BV
www.jasp-services.com
Reposted by Maarten Marsman
nikolasekulovski.bsky.social
🚨 New preprint: A Stochastic Block Prior for Clustering in Graphical Models

We introduce an SBM prior to detect/test clusters in Bayesian network models for binary & ordinal data. Includes R code & tutorial.

📄 osf.io/preprints/ps...
📚 Blog: www.nikolasekulovski.com/blog/post2/
OSF
osf.io
Reposted by Maarten Marsman
danielheck.bsky.social
I am looking forward to expanding the scope of my professorship by combining cognitive and statistical modeling with LLMs😊

There will be two job openings for postdoc positions soon - one starting in September 2025 and another one a year later.
unimarburg.bsky.social
🚀 930.000 Euro für #Psychologie -Forschung: Prof. Daniel Heck nutzt #KI, um psychologische Theorien präziser zu machen. Mithilfe von #LLMs sollen unscharfe Begriffe in messbare Modelle übersetzt werden – ein Schritt zu besseren Experimenten & klareren Erkenntnissen #Forschung uni-marburg.de/gDNQIi
Portrait Prof. Dr. Daniel Heck. Foto: Martin Schäfer
maartenmarsman.bsky.social
I could collect more data, and the Bayesian approach allows me to monitor the evidence (e.g., the BF) as the data come in. I could also include theory or results from earlier research and update my knowledge. This is the kind of cumulative science I like to see! :-)
maartenmarsman.bsky.social
The phrase about results "not providing a solid basis for cumulative science" is about edges with anecdotal evidence. If I do not have enough evidence to draw a conclusion about an edge, then any decision is "risky". I would be happy to learn this if my theory or intervention builds on the edge.
maartenmarsman.bsky.social
Interestingly, we also found evidence for the absence of many edges, a result that doesn't match the predictions of the unidimensional factor model, suggesting it wouldn't fit the data well. Thus, we likely need network or equivalently higher-order factor models to describe these data!
maartenmarsman.bsky.social
Hi Miri, I don’t think it’s about partial correlations but about model complexity, as Karoline said. Unidimensional factor models are also based on partial correlations and are often robust, but they also have far less parameters than network models.
Reposted by Maarten Marsman
karolinehuth.bsky.social
Are psychometric networks sufficiently supported by data such that one can be confident when interpreting its results? We analysed 294 psychometric networks from 126 papers with the Bayesian approach to address this question @jmbh.bsky.social Sara Ruth van Holst @maartenmarsman.bsky.social 🧵
psyarxivbot.bsky.social
Statistical Evidence in Psychological Networks: A Bayesian Analysis of 294 Networks from 126 Studies: http://osf.io/62ydg/
Reposted by Maarten Marsman
jmbh.bsky.social
Emotions are reactions to situations we encounter in daily life. In our new paper in Psych Review (psycnet.apa.org/fulltext/202...; with @oisinryan.bsky.social and @fdabl.bsky.social), we take a first step towards building a generative model for emotion dynamics based on this simple principle 1/4
maartenmarsman.bsky.social
This is a collaborative effort with amazing colleagues: Lourens Waldorp, Nikola Sekulovski, and @jmbh.bsky.social. 🙌 Thanks to this team for their hard work in advancing Bayesian methods in network analysis!
maartenmarsman.bsky.social
Why is this exciting? 🌟 Our Bayes factor test helps you distinguish the absence of evidence from the evidence of absence of a difference effect. 📊 This means you can actually quantify the support for the null hypothesis of parameter equivalence! 🎯