Magnus Johansson
LightNews LightNews
banner
pgmj.bsky.social
Magnus Johansson
@pgmj.bsky.social
2.3K followers 1.3K following 320 posts
PhD & lic. psychologist. Research specialist at Karolinska Institutet. R package for Rasch psychometrics: pgmj.github.io/easyRasch/
#openscience, #prevention, #psychometrics, #rstats, #photo
Posts Replies Media Videos
Pinned
pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Mar 11
My simulation study on item misfit detection in Rasch models is published. We should leave rule-of-thumb critical values for GOF metrics behind us and use simulation/bootstrap methods to determine cutoffs appropriate for the data and items being analyzed. pgmj.github.io/rasch_itemfit/ #psychometrics
Detecting item misfit in Rasch models
pgmj.github.io
Reposted by Magnus Johansson
xkcd.com
Fifteen Years

xkcd.com/3172/
Comic. Panels up to the 10-year point are grayed out. New panels since the Ten Years comic, which chronicles the first ten years of PERSON 1's journey with cancer: (1) [two people in bed] PERSON 1 (woman): One more chapter? PERSON 2 (man): Don’t we both have to get up early? PERSON 1: Nnnnnggggh PERSON 2: Sure, good point. (2) [many people wearing masks, walking while looking at graphs on their phones] (3) [birds landing on people] PERSON 2 in beanie and scarf: Hah! They like *my* seeds best. PERSON 1 in scarf holding phone with a bird sitting on it: Wait, how do I take a picture of this one? (4) [two people rowing boats with tree landscape] (5) [Person 1 carries overflowing stack of things to Person 2 in bed] PERSON 1: I brought you honey lemon tea, more pillows, a cinnamon roll, Tylenol, another blanket, a– PERSON 2: It was just Appendicitis, I’m really– PERSON 1: *It is my turn to take care of you and I am going to do it right!* (6) [Two people in car] (7) [still in car) PERSON 1: Oh my god. PERSON 2: Oh my god. (8) [car driving] PERSON 1: Pull over! PERSON 2: I am! (9) [both people get out of car] (10) [Large colored panel of aurora borealis over water with both people looking on] (11) [Person 1 sits against tree while Person 2 lies on the ground] PERSON 1: Fifteen years. No sign of the cancer. (12) I *am* having some weird symptoms. Joint pain. Fatigue. I think I’m losing my close-up vision. PERSON 2: Yeah. Me too. (13) PERSON 2: I think we’re getting old. (14) PERSON 1: I guess that’s okay. PERSON 2: It’s all I wanted.
November 26, 2025 at 10:32 PM
Reposted by Magnus Johansson
lorak.bsky.social
Meta halted internal research that purportedly showed (young) people who stopped using Facebook became less depressed and anxious, according to an unredacted legal filing released on Friday. www.cnbc.com/2025/11/23/m...
Meta halted internal research suggesting social media harm, court filing alleges
Meta is alleged to have halted internal research suggesting social media harm, according to court documents.
www.cnbc.com
November 24, 2025 at 12:31 AM
pgmj.bsky.social
More tinkering with relative measurement uncertainty proposed by @bignardi.bsky.social et al, using plausible values to estimate conditional reliability (inspired by @dmcneish.bsky.social) for Rasch models with WL estimation of latent scores. Code here: github.com/pgmj/easyRas...
November 21, 2025 at 8:29 AM
Reposted by Magnus Johansson
iandunt.bsky.social
They're going to crash the global economy by attempting to create an artificial general intelligence, despite having no idea what that is, no proof they can build it & no hope of doing so. Cunts just read too many sci-fi books.
November 12, 2025 at 3:12 PM
Reposted by Magnus Johansson
matti.vuorre.com
Everyone involved in scientific publishing should take a look at these papers.

>"The domination of scientific publishing in the Global North by major commercial publishers is harmful to science; we need [...] to re-communalise publishing to serve science not the market."
hansonmark.bsky.social Mark A. Hanson @hansonmark.bsky.social · 15d
We wrote the Strain on scientific publishing to highlight the problems of time & trust. With a fantastic group of co-authors, we present The Drain of Scientific Publishing:

a 🧵 1/n

Drain: arxiv.org/abs/2511.04820
Strain: direct.mit.edu/qss/article/...
Oligopoly: direct.mit.edu/qss/article/...
A table showing profit margins of major publishers. A snippet of text related to this table is below. 1. The four-fold drain 1.1 Money Currently, academic publishing is dominated by profit-oriented, multinational companies for whom scientific knowledge is a commodity to be sold back to the academic community who created it. The dominant four are Elsevier, Springer Nature, Wiley and Taylor & Francis, which collectively generated over US$7.1 billion in revenue from journal publishing in 2024 alone, and over US$12 billion in profits between 2019 and 2024 (Table 1A). Their profit margins have always been over 30% in the last five years, and for the largest publisher (Elsevier) always over 37%. Against many comparators, across many sectors, scientific publishing is one of the most consistently profitable industries (Table S1). These financial arrangements make a substantial difference to science budgets. In 2024, 46% of Elsevier revenues and 53% of Taylor & Francis revenues were generated in North America, meaning that North American researchers were charged over US$2.27 billion by just two for-profit publishers. The Canadian research councils and the US National Science Foundation were allocated US$9.3 billion in that year. A figure detailing the drain on researcher time. 1. The four-fold drain 1.2 Time The number of papers published each year is growing faster than the scientific workforce, with the number of papers per researcher almost doubling between 1996 and 2022 (Figure 1A). This reflects the fact that publishers’ commercial desire to publish (sell) more material has aligned well with the competitive prestige culture in which publications help secure jobs, grants, promotions, and awards. To the extent that this growth is driven by a pressure for profit, rather than scholarly imperatives, it distorts the way researchers spend their time. The publishing system depends on unpaid reviewer labour, estimated to be over 130 million unpaid hours annually in 2020 alone (9). Researchers have complained about the demands of peer-review for decades, but the scale of the problem is now worse, with editors reporting widespread difficulties recruiting reviewers. The growth in publications involves not only the authors’ time, but that of academic editors and reviewers who are dealing with so many review demands. Even more seriously, the imperative to produce ever more articles reshapes the nature of scientific inquiry. Evidence across multiple fields shows that more papers result in ‘ossification’, not new ideas (10). It may seem paradoxical that more papers can slow progress until one considers how it affects researchers’ time. While rewards remain tied to volume, prestige, and impact of publications, researchers will be nudged away from riskier, local, interdisciplinary, and long-term work. The result is a treadmill of constant activity with limited progress whereas core scholarly practices – such as reading, reflecting and engaging with others’ contributions – is de-prioritized. What looks like productivity often masks intellectual exhaustion built on a demoralizing, narrowing scientific vision. A table of profit margins across industries. The section of text related to this table is below: 1. The four-fold drain 1.1 Money Currently, academic publishing is dominated by profit-oriented, multinational companies for whom scientific knowledge is a commodity to be sold back to the academic community who created it. The dominant four are Elsevier, Springer Nature, Wiley and Taylor & Francis, which collectively generated over US$7.1 billion in revenue from journal publishing in 2024 alone, and over US$12 billion in profits between 2019 and 2024 (Table 1A). Their profit margins have always been over 30% in the last five years, and for the largest publisher (Elsevier) always over 37%. Against many comparators, across many sectors, scientific publishing is one of the most consistently profitable industries (Table S1). These financial arrangements make a substantial difference to science budgets. In 2024, 46% of Elsevier revenues and 53% of Taylor & Francis revenues were generated in North America, meaning that North American researchers were charged over US$2.27 billion by just two for-profit publishers. The Canadian research councils and the US National Science Foundation were allocated US$9.3 billion in that year. The costs of inaction are plain: wasted public funds, lost researcher time, compromised scientific integrity and eroded public trust. Today, the system rewards commercial publishers first, and science second. Without bold action from the funders we risk continuing to pour resources into a system that prioritizes profit over the advancement of scientific knowledge.
November 12, 2025 at 8:15 AM
Reposted by Magnus Johansson
solomonkurz.bsky.social
Two-group pre/post data are deceptively simple, and you could analyze them in many different ways, depending on your goals. Here are three blog posts on the topic:

solomonkurz.netlify.app/blog/2022-06...

solomonkurz.netlify.app/blog/2020-12...

solomonkurz.netlify.app/blog/2023-06...
November 10, 2025 at 7:19 PM
Reposted by Magnus Johansson
brendanmontague.bsky.social
“…the net worth of the 10 richest US billionaires grew by $698bn in the past year. That money alone, the increment in the wealth of 10 people, is almost 10 times the annual amount required to end extreme poverty worldwide.”

www.theguardian.com/commentisfre...
I wish we could ignore Bill Gates on the climate crisis. But he’s a billionaire, so we can’t | George Monbiot
Money talks – and his essay denouncing ‘near-term emissions goals’ at Cop30 mostly argues the case for letting the ultra-rich off the hook
www.theguardian.com
November 8, 2025 at 11:16 AM
Reposted by Magnus Johansson
jeffhorwitz.bsky.social
Meta earns $3.5 billion every six months from showing Faceboon and Instagram users 15 billion “higher legal risk” scam ad impressions a day, internal documents state.

That haul vastly exceeds how much the company expects regulators
To fine it for running scam ads.

www.reuters.com/investigatio...
www.reuters.com
November 6, 2025 at 11:46 AM
pgmj.bsky.social
Waiting for a new work Mac, I’m using an M1 Air 2020 which only has 4 high performance cores. Running some tests in R, the Air is twice as fast when using only 4 cores compared to using 8 cores (including the high efficiency cores).
November 5, 2025 at 11:49 AM
pgmj.bsky.social
I was just notified of another paper citing our paper as validating the Swedish PSS-4, when we actually conclude that it should not be used. What was even more surprising was that one of my coauthors on the psychometrics paper was also a coauthor on the paper. Not sure what to do with this.
pgmj.bsky.social Magnus Johansson @pgmj.bsky.social · Feb 21
A recent paper using the 4-item perceived stress scale is citing our PSS #psychometrics paper in the methods section. From our abstract: “the PSS-4 was not deemed suitable as a unidimensional scale”. They didn’t even read the abstract?! doi.org/10.1186/s128...
journals.sagepub.com/doi/full/10....
November 3, 2025 at 9:07 AM
Reposted by Magnus Johansson
rmkubinec.bsky.social
AI has an "emperor has no clothes" problem where people imagine there are geniuses who will inevitably achieve breakthroughs with enough cash.

AI is bottlenecked by limits in data availability, statistical mechanics, & computing. Improvements will be expensive & incremental, not fundamental.
cwarzel.bsky.social Charlie Warzel @cwarzel.bsky.social · 27d
so @matteowong.bsky.social & I wrote on data centers: arguably the most important buildings in the world & are, in a way, holding the economy hostage. Byzantine financial instruments, private equity, depreciating tech, hype, $trillion valuations. it’s all there. an ai crash prob starts here.
Here’s How the AI Crash Happens
The U.S. is becoming an Nvidia-state.
www.theatlantic.com
October 31, 2025 at 1:05 PM
pgmj.bsky.social
Forced to deal with Microsoft Outlook/etc at work, I constantly find the default settings to be annoying/stupid. I wonder if they ever gather data to understand user preferences or just make assumptions. Or am I the outlier?
a cartoon of a man in a suit and tie standing in front of a fire escape
ALT: a cartoon of a man in a suit and tie standing in front of a fire escape
media.tenor.com
October 31, 2025 at 10:38 AM
Reposted by Magnus Johansson
avehtari.bsky.social
I'm now also looking for a postdoc with strong Bayesian background and interest in developing Bayesian cross-validation theory, methods and software. Apply by email with no specific deadline (see contact information at users.aalto.fi/~ave/).

Others, please share
avehtari.bsky.social Aki Vehtari @avehtari.bsky.social · Oct 6
I'm looking for a doctoral student with Bayesian background to work on Bayesian workflow and cross-validation (see my publication list users.aalto.fi/~ave/publica... for my recent work) at Aalto University.

Apply through the ELLIS PhD program (dl October 31) ellis.eu/news/ellis-p...
ELLIS PhD Program: Call for Applications 2025
The ELLIS mission is to create a diverse European network that promotes research excellence and advances breakthroughs in AI, as well as a pan-European PhD program to educate the next generation of AI...
ellis.eu
October 29, 2025 at 2:37 PM
Reposted by Magnus Johansson
rpsychologist.com
New release of PowerLMM.js! Browser-based power analysis for longitudinal models with dropout.

Now includes:
- Power analysis summary report
- Reproducible & shareable configs (URL/JSON)
- Calculations validated against R
- Hypothesis region visualization

powerlmmjs.rpsychologist.com
October 28, 2025 at 2:02 PM
Reposted by Magnus Johansson
matti.vuorre.com
🎉 @rpsychologist.com 's PowerLMM.js is the online statistics application of the year 2025 🎉

powerlmmjs.rpsychologist.com

- Calculate power (etc) for multilevel models
- Examine effects of dropout and other important parameters
- Fast! (Instant results)
Screenshot of https://powerlmmjs.rpsychologist.com/
October 28, 2025 at 2:37 PM
Reposted by Magnus Johansson
djnavarro.net
in my post-academic era i have become extremely scathing of the way academia considers papers to the primary outcome of intellectual work, and refuses to give credit to academics who write software or build other tooling. in industry we very rarely read your papers; but we always use your software
October 28, 2025 at 2:15 AM
Reposted by Magnus Johansson
danlewer.bsky.social
We wrote an article explaining why you shouldn't put several variables into a regression model and report which are statistically significant - even as exploratory research. bmjmedicine.bmj.com/content/4/1/.... How did we do?
A "methods primer" article in the journal "BMJ Medicine", titled "Factors associated with: problems of using exploratory multivariable regression to identify causal risk factors"
October 27, 2025 at 5:39 PM
pgmj.bsky.social
I've done some more work on the relative measurement uncertainty, comparing `brms` posterior draws to "plausible values" in Rasch models, and some other reliability metrics. Estimating RMU from draws adds some variation, as shown in the figure.
pgmj.github.io/reliability....
#rstats #psychometrics
October 24, 2025 at 4:49 PM
Reposted by Magnus Johansson
v2action.bsky.social
Anthony Biglan's "The Nurture Effect" shines a light on how we can intentionally design better societies. It's about building upstream prevention and fostering nurturing environments. What are your thoughts? snapt.io/CUHnJ #SocialScience #CommunityDevelopment #Prevention Image: Vectzeey
October 23, 2025 at 8:47 PM
Reposted by Magnus Johansson
carlzimmer.com
Largest study of its kind shows AI assistants misrepresent news content 45% of the time – regardless of language or territory. www.bbc.co.uk/mediacentre/...
Largest study of its kind shows AI assistants misrepresent news content 45% of the time – regardless of language or territory
An intensive international study was coordinated by the European Broadcasting Union (EBU) and led by the BBC
www.bbc.co.uk
October 23, 2025 at 5:17 PM
Reposted by Magnus Johansson
forbesmm.bsky.social
this tweet turns 10 today 🎂🥳
Tweet from Adrian Bott @Cavalorn 'I never thought leopards would eat MY face,' sobs woman who voted for the Leopards Eating People's Faces Party.
October 16, 2025 at 9:25 PM
Reposted by Magnus Johansson
matti.vuorre.com
Against Publishing: universonline.nl/nieuws/2025/...

Preprints are read, shared, and cited, yet still dismissed as incomplete until blessed by a publisher. I argue that the true measure of scholarship lies in open exchange, not in the industry’s gatekeeping of what counts as published.
October 14, 2025 at 9:16 AM
pgmj.bsky.social
Very useful extension! I used an earlier version in this paper: pgmj.github.io/rasch_itemfit/
October 13, 2025 at 3:40 PM
Reposted by Magnus Johansson
brosen67.bsky.social
Legendary session bassist Leland Sklar added a switch to his bass that does nothing. He calls it the 'producer switch' -when a producer asks for a different sound, he flips the switch (making sure the producer can see) and carries on. He says this placebo has saved him a lot of grief. Bild: Leland Sklar med sin bas gör tummen upp
October 12, 2025 at 7:42 AM
pgmj.bsky.social
I agree. #openscience combined with #opensource software is great!
mzloteanu.bsky.social Dr Mircea Zloteanu 🍁 🍃 @mzloteanu.bsky.social · Oct 10
This is what I find awesome (in the truest sense) about scientific development in the modern age. One group posts a new technique and within a few days it is implemented by others. #rstats is magic (and efficient)
pgmj.bsky.social Magnus Johansson @pgmj.bsky.social · Oct 10
This is really neat. I have borrowed the reliability() function to my `easyRasch` package, and use plausible values instead of fully Bayesian estimation to produce similar estimates/CIs, see code example below. RMU point estimates are similar to EAP reliability.

pgmj.github.io/easyRasch/re...
October 11, 2025 at 9:02 AM