Magnus Johansson
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pgmj.bsky.social
Magnus Johansson
@pgmj.bsky.social
2.4K followers 1.3K following 340 posts

PhD & lic. psychologist. Research specialist at Karolinska Institutet. R package for Rasch psychometrics: pgmj.github.io/easyRasch/
#openscience, #prevention, #psychometrics, #rstats, #photo

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Sociology 12%
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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

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 4d
I'd ask the same question about any VAS rating scale.

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 12d
Sounds like a proper winter. Here it only rains and +2-7 C temp. Dark and dreary :(

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 13d
Linking to the actual research paper in the article would be helpful.

Reposted by Magnus Johansson

solomonkurz.bsky.social
Solomon Kurz @solomonkurz.bsky.social · 14d
Another day, and another reference to these bangers. Contemporary causal inference has fundamentally changed the way I think about control variables and mediation analyses. These can show you why:

doi.org/10.1177/2515...
doi.org/10.1111/spc3...
doi.org/10.1177/2515...
Sage Journals: Discover world-class research
Subscription and open access journals from Sage, the world's leading independent academic publisher.
doi.org

Reposted by Dorothy Bishop, David Chester, Andrew K Przybylski , and 5 more

ianhussey.mmmdata.io
Ian Hussey @ianhussey.mmmdata.io · 14d
Keeping this at hand in case I need to point to it and tap

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 14d
Just realized I have an old gdrive folder with similar content, if it could be of interest: drive.google.com/drive/mobile...
Funktionell kontextualism - Google Drive
drive.google.com

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 14d
Nice. This is also a great read: www.scribd.com/doc/29106580...
Gifford and Hayes - Functional Contextualism 1999 | PDF
Gifford and Hayes - Functional Contextualism 1999
www.scribd.com

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 15d
Might this be applicable? journals.sagepub.com/doi/10.1177/...
These Are Not the Effects You Are Looking for: Causality and the Within-/Between-Persons Distinction in Longitudinal Data Analysis - Julia M. Rohrer, Kou Murayama, 2023
In psychological science, researchers often pay particular attention to the distinction between within- and between-persons relationships in longitudinal data a...
journals.sagepub.com

Reposted by Alexander Wuttke, Magnus Johansson

ianhussey.mmmdata.io
Ian Hussey @ianhussey.mmmdata.io · 18d
Today’s example of “self reported behaviour is a poor proxy of behaviour”: environmental behaviour
cameronbrick.bsky.social Cameron Brick @cameronbrick.bsky.social · 18d
Also, "research involving self-reports often leads to fundamentally different results than research focusing on actual behavior in incentivized settings"

2/3

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 18d
Thanks, lots of interesting things discussed! Curious about why a zero-inflated or hurdle negbin was not used? ”We employ negative binomial regression models, which are well-suited to the outcome variable’s distribution — right-skewed with a large concentration of zero values.”

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 18d
Lägger till ett tips om ett spel som går utmärkt att köpa, och har en ovanlig mix av samarbete och tävling: www.webhallen.com/se/product/2...
Terraforming Mars (Eng) - Brädspel | Webhallen
www.webhallen.com

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 24d
You just need to install the `geomtextpath` package. Here is an intro vignette: allancameron.github.io/geomtextpath...
Introduction to geomtextpath
geomtextpath
allancameron.github.io

Reposted by Ian Hussey, Sebastian Karcher

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 24d
geomtextpath can really help make a plot easier to interpret. Nice to avoid using a legend. #rstats #dataviz
Two plots side by side showing time in weeks on x axis and probability of returning to work on the y axis. The left hand plot shows the trajectory of two groups (self-efficacy improved or not improved), while the right hand plot shows the probability difference between the two groups.

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 26d
Och återinföra arvsskatt när en rimligt hög nivå överstigs, vilket rent ideologiskt även borde gå i linje med liberala tankegångar.

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · 29d
Unless it's observational data? academic.oup.com/ije/article/...
Analyses of ‘change scores’ do not estimate causal effects in observational data
AbstractBackground. In longitudinal data, it is common to create ‘change scores’ by subtracting measurements taken at baseline from those taken at follow-u
academic.oup.com

Reposted by Suresh Venkatasubramanian, Philip N. Cohen, Magnus Johansson , and 5 more

xkcd.com
Randall Munroe @xkcd.com · Nov 26
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.

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 24
Link to blog does not work.

Reposted by Michael E. Mann, Jan W. Mueller, David Lazer , and 14 more

lorak.bsky.social
Lora Kolodny @lorak.bsky.social · Nov 24
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

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 23
Here is another paper on that topic that has some nice examples: www.tandfonline.com/doi/abs/10.1...

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 21
Respectable lists of some great movies! I think you forgot Return of the Jedi, though.

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 21
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...

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 15
I think there is some material on this in the current draft of the brms book.

Reposted by Magnus Johansson

iandunt.bsky.social
Ian Dunt @iandunt.bsky.social · Nov 12
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.

Reposted by Magnus Johansson

matti.vuorre.com
Matti Vuorre @matti.vuorre.com · Nov 12
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 · Nov 11
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.

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 10
Maybe try altdoc.etiennebacher.com

Reposted by Magnus Johansson, Jill A. Jacobson

solomonkurz.bsky.social
Solomon Kurz @solomonkurz.bsky.social · Nov 10
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...

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 10
I think the impact is pretty clearly disastrous. But can't blame the paper for all of it's misuse. See for instance:
journals.sagepub.com/doi/full/10....
Sage Journals: Discover world-class research
Subscription and open access journals from Sage, the world's leading independent academic publisher.
journals.sagepub.com

Reposted by Magnus Johansson

brendanmontague.bsky.social
Brendan @brendanmontague.bsky.social · Nov 8
“…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

Reposted by Brendan Nyhan, Leigh Sparks, Cathy N. Davidson , and 8 more

jeffhorwitz.bsky.social
Jeff Horwitz @jeffhorwitz.bsky.social · Nov 6
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

pgmj.bsky.social
Magnus Johansson @pgmj.bsky.social · Nov 5
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).