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Peder M Isager

@isager.bsky.social
388 followers 98 following 103 posts

Associate professor at Oslo New University College. Dungeon Master. Website: pedermisager.netlify.app

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Peder M Isager @isager.bsky.social · 11/08/2026
Perspectives on Scientific Error 2027 is heading to Copenhagen, Jan 27th to 29th PSE brings together philosophers of science, statisticians and metascientists around 1 question: how do errors get into the scientific record, and what can we do about them? Register your interest at errorsin.science
errorsin.science
Perspectives on Scientific Error 2027 · PSE9
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Peder M Isager @isager.bsky.social · 11/08/2026
In practice, I think I would normally recommend a sequential analysis approach with a max N set to the number of participants you can afford, but with the option of stopping early if power is high for the TST before max N is reached. lakens.github.io/statistical_...
lakens.github.io
10  Sequential Analysis – Improving Your Statistical Inferences
This open educational resource contains information to improve statistical inferences, design better experiments, and report scientific research more transparently.
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Peder M Isager @isager.bsky.social · 11/08/2026
I agree it is a tricky issue. The true size of the effect relative to the SESOI bounds obv matters for power. This applies both to the TOST (true effect can be within SESOI bounds but not 0, and to superiority (true effect can be >SESOI but distance from SESOI matters).
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Constantin Späth @cspaeth.bsky.social · 08/07/2026
@isager.bsky.social I just saw that you illustrated a thought experiment ("Insomnia Treatment Experiment") when explaining power planning for TST. But also in this example it is basically (inductively informed) guesswork, isn't it? -> journals.sagepub.com/doi/full/10....
journals.sagepub.com
Three-Sided Testing to Establish Practical Significance: A Tutorial - Peder Mortvedt Isager, Jack Fitzgerald, 2026
Researchers may want to know whether an observed statistical relationship is either meaningfully negative, meaningfully positive, or small enough to be consider...
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Melissa Kline Struhl @mekline.bsky.social · 05/05/2026
Psych-DS is spellcheck for your datasets, and it has an R package now! Available in beta now, made by the excellent Brian Leonard, instructions here: psych-ds.github.io/psychds-r/
Screenshot of the "Create Dataset" page of the psych-DS Shiny app from the new R package psychds
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Peder M Isager @isager.bsky.social · 28/04/2026
My article "Three-Sided Testing to Establish Practical Significance" with @jackfitzgerald.bsky.social is now published in AMPPS! journals.sagepub.com/doi/10.1177/... Three-sided testing is an improved version of TOST that lets you test for equivalence, superiority and inferiority simultaneously.
journals.sagepub.com
Sage Journals: Discover world-class research
Subscription and open access journals from Sage, the world's leading independent academic publisher.
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Daniel Lakens @lakens.bsky.social · 30/01/2026
New episode of Nullius In Verba! We discuss the jingle-jangle fallacy, the problem of vague concepts, how the incentive structures promote vagueness, why people who prefer more rigour have to be called the validity 'police', and much more! nulliusinverba.podbean.com/e/episode-74...
nulliusinverba.podbean.com
Episode 74: Notiones Vague | Nullius in Verba
In this episode, we discuss the problems associated with vague concepts in psychological science. We talk about the jingle-jangle fallacy, the trade-off between broad concepts and more precise…
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Peder M Isager @isager.bsky.social · 29/01/2026
Being able to explain which replication efforts are important and why should be helpful both when asking for funding, when convincing journals to take a replication report, and when motivating reserarchers to take on replication in their own work. Thanks so much for helping to move the discussion!
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Peder M Isager @isager.bsky.social · 29/01/2026
Wonderful! So happy to hear that workshops are including discussion on this :) I think giving researchers clearer direction on how to formulate replication goals and use them to pick targets is going to help a lot with actually getting more replications done in practice.
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Julia M. Rohrer @dingdingpeng.the100.ci · 29/01/2026
Just learned about this study looking at methodological trends in psych and econ over time: online.ucpress.edu/collabra/art.... Matches my perception well: Nobody in psych bothers to (explicitly) try causal inference unless they conducted an experiment, not a lot of theoretical work either.
Figure 1 from the paper.
Econ: from 2008 to 2024, methods aiming for causal inference have increased, theoretical work has decreased. 
Psych: Mostly experimental or descriptive correlational work.
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Peder M Isager @isager.bsky.social · 29/01/2026
Very cool to hear! What was the topic of the workshop? :)
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Peder M Isager @isager.bsky.social · 29/01/2026
Very cool. Speaking of front-door, I have also added features to let you statistically control for variables in the DAG to simulate e.g. back-door criterion.
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Peder M Isager @isager.bsky.social · 29/01/2026
Because of course the Germans have their own Pokémon names 😂 Take notes, Språkrådet!
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Peder M Isager @isager.bsky.social · 28/01/2026
New blog post introducing Causion - a web app for causal inference teaching and learning: pedermisager.org/blog/causion....
pedermisager.org
Introducing Causion: A web app for playing with DAGs | Peder M. Isager
Personal website of Dr. Peder M. Isager
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Peder M Isager @isager.bsky.social · 28/01/2026
... generate a "plausible" DAG for your research problem that you can play with and simulate data from. I had some success with this for a class project already. Not guaranteed to work of course (AI is not very good at causal inference yet), but it might be worth a try!
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Peder M Isager @isager.bsky.social · 28/01/2026
3. If you are working in a field with a large existing literature, you may have some success collaborating with AI to create a plausible SCM for the effects you are studying, including likely confounders, mediators, etc. You can copy-paste such SCMs into the SCM panel of Causion to automatically....
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Peder M Isager @isager.bsky.social · 28/01/2026
2. You might find the "simulate data" feature in Causion interesting. For example, you can simulate data with a certain level of noise and plug that data into a statistical analysis program to help design an analysis plan for identifying causal effects that you can then preregister.
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Peder M Isager @isager.bsky.social · 28/01/2026
... to communicate your causal beliefs to them than verbally stating the causal relationships you think are at play. Since Causion is a DAG drawing tool, it can help you with this process.
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Peder M Isager @isager.bsky.social · 28/01/2026
That is a very interesting use case. I think you might find three features particularly interesting. 1. DAGs help to formalize intuitions. If you have verbal theories about variables involved in your research and how they're related, presenting your readers with a DAG is often a much clearer...
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Peder M Isager @isager.bsky.social · 28/01/2026
Please do! I am also planning to use it for teaching in the coming months. All feedback and suggestions for fixes and improvements are most welcome! Because I am building with Codex I can normally implement fixes and changes to the UI (like adding buttons etc.) quite fast.
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Peder M Isager @isager.bsky.social · 28/01/2026
Thanks! It is lightly inspired by the Star Treck Discovery intro :)
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Peder M Isager @isager.bsky.social · 28/01/2026
Tagging some potentially interested people: @raphaelmerz.bsky.social @dingdingpeng.the100.ci @jamessteeleii.bsky.social @epiellie.bsky.social @elluetravel.bsky.social @annemscheel.bsky.social @lakens.bsky.social @annaveer.bsky.social @pwgtennant.bsky.social @fdabl.bsky.social @nickchk.com
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Peder M Isager @isager.bsky.social · 28/01/2026
NB: The app is coded with the help of ChatGPT Codex. I have tested it as well as I can, but it may contain bugs and errors. If you spot any, let me know and I will fix them.
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Peder M Isager @isager.bsky.social · 28/01/2026
The app will always be free to use, and the app code is open source on Github: github.com/pederisager/....
github.com
GitHub - pederisager/causion: An app for visualizing the expected consequences of changing variable values in a DAG. Gain an intuition for the relationship between correlation and causation. Created w...
An app for visualizing the expected consequences of changing variable values in a DAG. Gain an intuition for the relationship between correlation and causation. Created with ChatGPT. - GitHub - pe...
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Peder M Isager @isager.bsky.social · 28/01/2026
I hope Causion can be of use to methods teachers and students who want to learn about causal inference and its role in statistics. The app is designed to be easy to use interactively (e.g. as part of a lecture, or to whip up an example from a course book while reading).
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Peder M Isager @isager.bsky.social · 28/01/2026
If you want to try it out, I’ve posted a tutorial video on youtube that explains all the core functionality: www.youtube.com/watch?v=C3fb....
youtube.com
Causion App Tutorial: Build, manipulate, and simulate data from DAGs
YouTube video by Peder Isager
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Peder M Isager @isager.bsky.social · 28/01/2026
The app is available online at causion.pedermisager.org
causion.pedermisager.org
causion-app
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Peder M Isager @isager.bsky.social · 28/01/2026
For many years I’ve wanted a tool to help me visualize causal inference rules, ”play out” causal mechanisms in DAGs, and quickly study what happens in data when I change something in a DAG. Causion lets me do all of this in a simple and intuitive way.
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Peder M Isager @isager.bsky.social · 28/01/2026
New blog post introducing Causion - a web app for causal inference teaching and learning: pedermisager.org/blog/causion....
pedermisager.org
Introducing Causion: A web app for playing with DAGs | Peder M. Isager
Personal website of Dr. Peder M. Isager
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Peder M Isager @isager.bsky.social · 28/01/2026
That's what I was thinking of at least :) The paper, all commentaries and our response to commentaries are now all open access in Meta-Psychology: open.lnu.se/index.php/me...
open.lnu.se
LnuOpen | Meta-Psychology
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Björn E. Hommel @bjoernhommel.bsky.social · 26/11/2025
🚨 SynthNet is out 🚨 Researchers propose new constructs and measures faster than anyone can track. We (@anniria.bsky.social @ruben.the100.ci) built a search engine to check what already exists and help identify redundancies; indexing 74,000 scales from ~31,500 instruments in APA PsycTests. 🧵1/3
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Peder M Isager @isager.bsky.social · 24/11/2025
Regardless, this issue does pose problems for the usefulness of RV. I discuss this some in my PhD thesis discussion. See figure 6.3.C for a similar example: pure.tue.nl/ws/portalfil...
pure.tue.nl
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Peder M Isager @isager.bsky.social · 24/11/2025
Test severity may at once improve the ability of a replication study to reduce uncertainty, but it can also leave less uncertainty to be reduced to begin with.
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Peder M Isager @isager.bsky.social · 24/11/2025
”paradox: test severity seems to imply both increased and reduced uncertainty reduction, depending on how you think about it” I think this is not a paradox per se. Rather, I think test severity can have two causal effects that work against each other.
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Peder M Isager @isager.bsky.social · 24/11/2025
I think it is possible to reduce uncertainty about such claims through replication, even without a SESOI (e.g. if you’re willing to be a Bayesian).
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Peder M Isager @isager.bsky.social · 24/11/2025
”we need a SESOI and an equivalence-test framework”. On the one hand I agree, but on the other hand, many scientific claims are not related to a SESOI. The claim is simply ”drug A works better than drug B”, ”there is a positive correlation between X and Y”, and so on.
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Peder M Isager @isager.bsky.social · 24/11/2025
Thanks for sharing your thoughts, this is definitely a worthwhile problem to consider. Let me share some unfinished thoughts of my own:
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Peder M Isager @isager.bsky.social · 17/11/2025
The post is a light and practical introduction to causal inference with variable control. It assumes som familiarity with regression analysis, and it helps to read my previous posts on causal inference, but that is it. Links to more in-depth literature on the topic are provided in references.
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Peder M Isager @isager.bsky.social · 17/11/2025
I am currently experimenting with AI-augmentation of my educational materials. This post includes a NotebookLM video summary for those out there who prefer video tutorials to written summaries: youtu.be/EYTNzfHmTvc. The video does not replace the post, but provides a decent high-level summary.
youtu.be
Which variables to control for, and why
YouTube video by Peder Isager
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Peder M Isager @isager.bsky.social · 17/11/2025
and why adjusting for the wrong ones can introduce new, serious biases. The post features a worked example in Jamovi using simulated data. All files available on OSF >
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Peder M Isager @isager.bsky.social · 17/11/2025
New blog post! ”Which variables to control for, and why”: pedermisager.org/blog/which-v... In this post I give a beginner-friendly introduction to causal inference and statistical control, explaining why adjusting for the right variables clarifies relationships >
pedermisager.org
Which variables to control for, and why | Peder M. Isager
Personal website of Dr. Peder M. Isager
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Raphael Merz @raphaelmerz.bsky.social · 13/11/2025
Join the next PMGS workshop where @ambra-prg.bsky.social will explain how to use Quarto for your reproducible research! 🔓🧑‍🔬
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Peder M Isager @isager.bsky.social · 30/10/2025
Thanks to all the commentary authors for your contributions, and thanks especially to the editors at Meta-psychology especially for allowing us to test out this format for our publication. It was a long road, but the end result is in my opinion terrific!
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Peder M Isager @isager.bsky.social · 30/10/2025
Quantifying replication value as a combination of citation count and sample size is our first stab at solving a very complex problem. Such early attempts benefit enormously from being critiqued right away. We were really lucky to receive several excellent commentaries from many experts in the field.
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Peder M Isager @isager.bsky.social · 30/10/2025
This paper forms one of Meta-Psychology’s Special Topics. Eight commentaries have been published alongside the paper which criticizes and extends the ideas presented within. We have written a response to these commentaries here: open.lnu.se/index.php/me...
open.lnu.se
LnuOpen | Meta-Psychology
Bakker, B. N., Bomm, L., & Peterson, D. (2025). Commentary on Isager et al. (2021) Reflections on the Replication Value (RV) and a Proposal for Revision. Meta-Psychology, 9. https://doi.org/10.15626/MP.2024.4324
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Peder M Isager @isager.bsky.social · 30/10/2025
My paper with @lakens.bsky.social and @annaveer.bsky.social - “Replication value as a function of citation impact and sample size” - has just been published in Meta psychology! open.lnu.se/index.php/me...
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Ruben C. Arslan @ruben.the100.ci · 28/10/2025
I built a DAG diagram with garden hoses for teaching. Pictured: a collider bias diagram, inspired by a blocked pipe situation I experienced (which I credit with giving me the intuition though it also ruined my belongings in the flooded cellar).
me with some garden hoses connected in a  X -> Z <- Y fashion. If I shut the valve at Z, water from X spills out at Y
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Peder M Isager @isager.bsky.social · 26/09/2025
Indeed, I'm looking forward!
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Peder M Isager @isager.bsky.social · 26/09/2025
Extremely honored to recieve Oslo New University College's science award for 2025. ONH has been a fantastic base to conduct my research at for the past 4 years, and I have an amazing team of colleagues around me to thank for that. From the bottom of my heart, thank you all!
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