Fridtjof Petersen
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fridtjofptrsn.bsky.social
Fridtjof Petersen
@fridtjofptrsn.bsky.social
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PhD student in Psychometrics & (Bio)statistics @ University of Groningen, NL
Time Series | Survival Analysis | Joint Models | Prediction
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Reposted by Fridtjof Petersen
bsiepe.bsky.social
We built the openESM database:
▶️60 openly available experience sampling datasets (16K+ participants, 740K+ obs.) in one place
▶️Harmonized (meta-)data, fully open-source software
▶️Filter & search all data, simply download via R/Python

Find out more:
🌐 openesmdata.org
📝 doi.org/10.31234/osf...
October 22, 2025 at 7:34 PM
Reposted by Fridtjof Petersen
bringmannlaura.bsky.social
Looking for a PhD position? Come work with me! 🤩
In this PhD project, you will study how decisions in medicine (at the intensive care) can be improved using tools like algorithmic advice in both academic and hospital settings.
Talking Dutch is a plus! 😊
www.academictransfer.com/en/jobs/3514...
PhD Gut Feeling or Algorithm? Predicting Patient Outcomes in Critical Care
PhD Gut Feeling or Algorithm? Predicting Patient Outcomes in Critical Care (0.8-1.0 FTE) Do you want to cont
www.academictransfer.com
April 22, 2025 at 4:39 PM
Reposted by Fridtjof Petersen
bsiepe.bsky.social
Can we use features of dynamic networks (e.g. centrality) to improve treatment selection and outcome prediction?

New preprint on the topic: We highlight the role of uncertainty & introduce a Bayesian multilevel approach for uncertainty quantification of network features 🧵
osf.io/preprints/ps...
Image with three main boxes with recommendations for applied researchers on conceptualization, estimation, and interpretation when using network features. Conceptualization: - Discuss why a network feature should be relevant for a given treatment or outcome - Consider plausible effect size and sample size needed to detect an association with a distal outcome Estimation: - Carefully choose preprocessing and network estimation methods - Follow good practices for predictive models (e.g., cross-validation, out-of-sample validation) Interpretation: - Consider uncertainty in node selection and network feature regression - Compare network features with simpler time series features (e.g., person-specific mean or SD)
April 28, 2025 at 8:31 AM
Reposted by Fridtjof Petersen
millapihlajamaki.bsky.social
The first preprint from my PhD is out: osf.io/preprints/ps...! 🥳

We explored the temporal dynamics of four careless responding indicators (response time, within-beep standard deviation, an inconsistency index, occasion-person correlation) in ESM data across different samples.

Thread below🧵
OSF
osf.io
February 27, 2025 at 8:38 AM
Reposted by Fridtjof Petersen
bringmannlaura.bsky.social
If you do ESM research, please fill out this Short ESM Survey on open-ended items. 🤓
You can fill it out even if you do not use open-ended items in your own ESM research (will be even shorter 😊) rug.eu.qualtrics.com/jfe/form/SV_...
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Measurement Is The New Black -
We are a group of scientists interested in improving the validity of time-series measurement in social sciences.
www.mitnb.org
March 3, 2025 at 3:56 PM
Reposted by Fridtjof Petersen
aljoscharimpler.bsky.social
Excited to share that my first PhD paper got published! We explored the effects of correctly vs. failing to model true interactions in data. Can model misspecification lead to reversed conclusions? Which model generalizes better to a larger sample?

Read the article here: doi.org/10.3758/s134...
To interact or not to interact: The pros and cons of including interactions in linear regression models - Behavior Research Methods
Interaction effects are very common in the psychological literature. However, interaction effects are typically very small and often fail to replicate. In this study, we conducted a simulation compari...
doi.org
February 12, 2025 at 12:11 PM