If post-hoc power calculations are bad, why are post-hoc effective calculations good? replicationindex.com/2026/05/31/t...

Science is self-correcting, but it can take time. replicationindex.com/2026/05/28/w...

Excellent news! Nature is expanding Registered Reports to all the fields in which they publish! A great result by all those proposing this strong solution to publication bias and selective reporting (and getting expert feedback before data collection)! www.nature.com/articles/d41...

Communication, are you listening … ? So far, not a single @icahdq.bsky.social journal has implemented Registered Reports. Doesn’t reflect well on our field.

What is the difference between academics and scientists? Academics: Can I get this published? Scientists: Does this make a contribution?

Happiness measurement If you are happy and you know it l, clap your hands. If ... and you don't know it, take the IAT. 🤣

#MetaScience How useful are open data when we do not have open results? (At least APA does not claim to be a scientific organization) replicationindex.com/2026/05/16/o...

psychological science's meta-problem. There are problems. That is not a problem. Problems can be fixed. The meta-problem is that psychologists are unable and unwilling to fix problems. #ArrestedDevelopmentDisorder

The biggest problem in academia are the smartest people with false beliefs. Their intelligence blinds them to see their own mistakes. replicationindex.com/2026/05/12/s...

The replication crisis In 1990, Cohen said "less is more" Social psychologists heard "less power, means more studies". Then people asked for replications. The rest is history. The End.

Z-curve does not work, when users confuse EDR and ERR. No kidding. Maybe I should sell certification for the use of z-curve. replicationindex.com/2026/05/08/z...

The biggest obstacle to open science is open admission of mistakes. Even the Executive Director of the Center for Open Science struggles with it. replicationindex.com/2026/05/01/o...

40 years ago we were chanting "Ami's go home". It is time for Europe to defend itself. It's values were always different from those in the USA, especially the Confederate states that are now in charge.

Effect size distributions (ESDs) can help determine small/medium/large effects, but publication bias may lead to imprecision. Iceberg plots visualize a raw ESD against a pub bias-adjusted ESD. Build this using data typically reported in published meta-analyses via our new ‘ESDist’ R package 📦

IAT = Invalid Association Test replicationindex.com/2025/12/02/i...

Around 2000s, heavy weights Kahneman and Seligman entered wellbeing / happiness research and messed it up. Now it is time to return to Diener (1984) and SWB. There is no single happiness. SWB acknowledges this and let's people decide what happiness is for them. replicationindex.com/introduction...

Too bad there are no unsuccessful experiments in psychology and with every "success" a new paradigm is born.

#metascience Open science has improved transparency, but transparency is not the same as credibility.

Who said science is not self-correcting? We are now replacing p-curve with z-curve. @urisohn.bsky.social @datacolada.bsky.social www.tandfonline.com/doi/full/10....

50% is few??????????????

Based on what evidence? Gelman doesn't know shit about meta-science.

#Metascience You probably are a "better" scientist than Ioannidis. Compute your quality adjusted H-Index. replicationindex.com/2026/04/24/a...

There was no replication crisis in the social sciences. It was a replication crisis in psychology and it was primarily the result of experimental work in mainstream psychology being extremely under-theorised.

This project is part of the collaborative grant application @sajedehra.bsky.social described here: bsky.app/profile/saje.... You will be working with my team - do reach out to any current or past lab members to learn why this is a great environment to do metascientific research.

We are inviting applications for a two-year postdoctoral position in a collaborative meta-science project on the effectiveness of data and code sharing policies in research-performing organizations. www.tue.nl/en/working-a...

How replicable are results in the social sciences? It depends, but on what? Closeness of replication and strength of evidence! 100% for high quality studies with strong evidence!!! "Insanity is doing a different study and expecting the same result!" (Einstein) replicationindex.com/2026/04/13/h...

Replicability is 44, is about as meaningful as saying the meaning of life is 42. Here I show how we can move on from estimating average replicability. replicationindex.com/2026/04/13/h...

Another biased p-curve estimate. 99% power. LOL Uri blames the data.

Evidential value across established and emerging disease associations: A P-Curve and Z-curve analysis of Periodontal Disease literature #NeuroDegeneration 🧪🧠 https://www.researchsquare.com/article/rs-9377174/latest

#Metascience Science is self-correcting, academics are not. Here is a case study of an academic avoiding to admit that their method is flawed. replicationindex.com/2026/04/08/t...

New blog post (it's been a while): Make Meta-Analysis Great Again. This is a serious proposal. Please amplify to whoever might be interested, especially if they have money. steamtraen.blogspot.com/2026/04/make...

The Journal of Pseud-Scientific Psychology that published the Bem paper hasn't really changed despite badges, adversarial collaborations, and multiverse analyses. The real test is openness to real criticism. replicationindex.com/2025/12/05/w...

David against Goliath, Asterix against the Roman empire. We love the underdog. Well, here the underdog in statistics lands a punch in the face of giant Gelman. Two statisticians who want to remain anonymous verified the claim. replicationindex.com/2026/04/02/g...

I bet $1,000 that this claim is false. How can economics be worse than psychology that has 90% success rates and less than 50% power and sample sizes in the double digits. Something went wrong here somewhere for such a general claim.

A history of the top marginal tax rates on the wealthiest Americans: 1940: 81% 1950: 84% 1960: 91% 1970: 72% 1980: 70% 1990: 28% 2000: 40% 2010: 35% For 50 years, corporate backed politicians in Congress have slashed taxes to line the pockets of their wealthy donors.

Gelman tells us how to respond to criticism. But what if the criticism is invalid? Here I show how to respond to valid and invalid criticism. replicationindex.com/2026/03/31/l...

When a 5,000 citation paper gets shredded, does it make a sound? (not when word war III is happening).

#Metascience Button et al.'s Power Failure is a seminal meta-science paper. But it has a major flaw. It confuses unconditional power (median power of all studies, 21%) with conditional power (power / H1 is true). This has big implications for discussions of false positives.

When three reviewers (1 human, 2 AI) spot the same fatal flaw, why did the authors not see it or ask AI for a pre-submission review? replicationindex.com/2026/03/05/d...

Oversight Democrats have been investigating the handling of serious allegations by a survivor against Donald Trump when she was a minor. We have now confirmed that some of the documents related to this survivor appear to be missing from the files. Here’s what we know ⬇️

Meta-psychology is the scientific study of psychological scientists' behavior. They like z-curve as much, as rats liked a Skinner box. Too bad. Now you know how it feels to be a subject and not a participant.

Blogging is therapy. replicationindex.com/2026/02/18/a...

Babbage, 1830, discussing the problem that scientists selectively report findings that they want to be true. Confirmation bias is a strong human tendency. This is why we need to design science in a way that prevents conformation bias from leading us away from the truth.

In standard scientific reports in psych 96% of first mentioned main hypotheses are supported. In Registered Reports, this is 46%. The 96% is clearly biased (given true H1 rate and power). Lack of transparency means we do not know the true baserate. journals.sagepub.com/doi/10.1177/...

The replication crisis is only over when psychology journals stop publishing such biased articles that blame replication failures on replicators and not the use of p-hacking in original studies. Pathetic. replicationindex.com/2026/02/13/r...

Is this finally the baseball quote, where somebody compared their 1/3 success rate to a 33% batting average in baseball?

I think it's best for everyone to understand that the unified class project of billionaires right now is to do to white collar workers what globalization and neoliberalism did to blue collar workers.

A Federal judge in Oregon ruled that ICE can NOT use chemicals on protestors for exercising their 1st amendment rights. youtu.be/gvL9ckyrDTM?...

I am not a doctor. I am a doctor of philosophy. That just means I doctored my dissertation. 😃😁😇