Uri Simonsohn
Biographic Data
| ID | 195776 |
|---|---|
| NAME | Uri Simonsohn |
| GIVEN NAMES | Uri |
| FAMILY NAME | Simonsohn |
| SIGNATURE | SIMONSOHN U |
| AFFILIATIONS | University of Pennsylvania |
| ORCID | 0000-0002-8601-7211 |
| VERIFIED | Yes |
| TOTAL WORKS | 21 |
| TOTAL CITATIONS | 174 |
| AUTHOR COUNT | 21 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2006 |
| LATEST PUBLICATION YEAR | 2025 |
| H-INDEX | 6 |
Stimulus sampling reimagined: Designing experiments with mix-and-match, analyzing results with stimulus plots
Stimuli selection in psychology experiments is typically unsystematic, undocumented, and irreproducible. This makes confounds likely to arise. The statistical analysis of psychology experiments with multiple stimuli, in turn, is typically reported at the aggregate level, averaging across stimuli. This makes confounds unlikely to be detected. Here, we propose changing both the design and analysis of psychology experiments. We introduce "Mix-and-Ma…
Specification curve analysis
Psychology's Renaissance
In 2010–2012, a few largely coincidental events led experimental psychologists to realize that their approach to collecting, analyzing, and reporting data made it too easy to publish false-positive findings. This sparked a period of methodological reflection that we review here and call Psychology's Renaissance. We begin by describing how psychologists’ concerns with publication bias shifted from worrying about file-drawered studies to worrying a…
Two Lines: A Valid Alternative to the Invalid Testing of U-Shaped Relationships With Quadratic Regressions
Many psychological theories predict U-shaped relationships: The effect of x is positive for low values of x, but negative for high values, or vice versa. Despite implying merely a change of sign, hypotheses about U-shaped functions are tested almost exclusively via quadratic regressions, an approach that imposes an arbitrary functional-form assumption that in some scenarios can lead to a 100% rate of false positives (e.g., the incorrect conclusio…
A manifesto for reproducible science
Improving the reliability and efficiency of scientific research will increase the credibility of the published scientific literature and accelerate discovery. Here we argue for the adoption of measures to optimize key elements of the scientific process: methods, reporting and dissemination, reproducibility, evaluation and incentives. There is some evidence from both simulations and empirical studies supporting the likely effectiveness of these me…
Small Telescopes: Detectability and the Evaluation of Replication Results
This article introduces a new approach for evaluating replication results. It combines effect-size estimation with hypothesis testing, assessing the extent to which the replication results are consistent with an effect size big enough to have been detectable in the original study. The approach is demonstrated by examining replications of three well-known findings. Its benefits include the following: (a) differentiating “unsuccessful” replication …
Promoting an open research culture
Author guidelines for journals could help to promote transparency, openness, and reproducibility
Promoting Transparency in Social Science Research
Social scientists should adopt higher transparency standards to improve the quality and credibility of research.
P-curve: A key to the file-drawer.
Because scientists tend to report only studies (publication bias) or analyses (p-hacking) that "work," readers must ask, "Are these effects true, or do they merely reflect selective reporting?" We introduce p-curve as a way to answer this question. P-curve is the distribution of statistically significant p values for a set of studies (ps < .05). Because only true effects are expected to generate right-skewed p-curves-containing more low (.01s) th…
P -Curve and Effect Size: Correcting for Publication Bias Using Only Significant Results
Journals tend to publish only statistically significant evidence, creating a scientific record that markedly overstates the size of effects. We provide a new tool that corrects for this bias without requiring access to nonsignificant results. It capitalizes on the fact that the distribution of significant p values, p-curve, is a function of the true underlying effect. Researchers armed only with sample sizes and test results of the published find…
Life after P-Hacking
A 21 Word Solution
False-Positive Psychology: Undisclosed Flexibility in Data Collection and Analysis Allows Presenting Anything as Significant
In this article, we accomplish two things. First, we show that despite empirical psychologists’ nominal endorsement of a low rate of false-positive findings (≤ .05), flexibility in data collection, analysis, and reporting dramatically increases actual false-positive rates. In many cases, a researcher is more likely to falsely find evidence that an effect exists than to correctly find evidence that it does not. We present computer simulations and …
In defense of diligence: A rejoinder to Pelham and Carvallo (2011)
In Simonsohn (2011) I reported the results from 14 studies that suggest all existing evidence of implicit egotism in marriage, job, and location decisions is spurious. Lack of diligence by Pelham and colleagues explains in great part why the confounds behind their findings were not addressed in time. They almost never included controls, were dismissive of blatant alternative explanations, and on occasion misreported factual information that made …
Spurious? Name similarity effects (implicit egotism) in marriage, job, and moving decisions
Three articles published in the Journal of Personality and Social Psychology have shown that a disproportionate share of people choose spouses, places to live, and occupations with names similar to their own. These findings, interpreted as evidence of implicit egotism, are included in most modern social psychology textbooks and many university courses. The current article successfully replicates the original findings but shows that they are most …
Weather To Go To College
Does current utility bias predictions of future utility for high stakes decisions? Here I provide field evidence consistent with such Projection Bias in one of life's most thought-about decisions: college enrolment. After arguing and documenting with survey evidence that cloudiness increases the appeal of academic activities, I analyse the enrolment decisions of 1,284 prospective students who visited a university known for its academic strengths …
Friends of Victims: Personal Experience and Prosocial Behavior
Why do different people give to different causes? We show that the sympathy inherent to a close relationship with a victim extends to other victims suffering from the same misfortunes that have afflicted their friends and loved ones. Both sympathy and donations are greater among those related to a victim, and they are greater among those in a communal relationship as compared to those in an exchange relationship. Experiments that control for info…
New Yorkers Commute More Everywhere: Contrast Effects in the Field
Previous experimental research has shown that people's decisions can be influenced by options they have encountered in the past. This paper uses PSID data to study this phenomenon in the field, by observing how long people commute after moving between cities. It is found, as predicted, that (i) people choose longer commutes in a city they have just moved to, the longer the average commute was in the city they came from and (ii) when they move aga…
New Yorkers Commute More Everywhere: Contrast Effects in the Field
Previous experimental research has shown that people's decisions can be influenced by options they have encountered in the past. This paper uses PSID data to study this phenomenon in the field, by observing how long people commute after moving between cities. It is found, as predicted, that (i) people choose longer commutes in a city they have just moved to, the longer the average commute was in the city they came from, and (ii) when they move ag…
Clouds make nerds look good: Field evidence of the impact of incidental factors on decision making
Abundant experimental research has documented that incidental primes and emotions are capable of influencing people's judgments and choices. This paper examines whether the influence of such incidental factors is large enough to be observable in the field, by analyzing 682 actual university admission decisions. As predicted, applicants' academic attributes are weighted more heavily on cloudier days and non‐academic attributes on sunnier days. The…
Mistake: The Effect of Previously Encountered Prices on Current Housing Demand
Based on contrast effects studies from psychology, we predicted that movers arriving from more expensive cities would rent pricier apartments than those arriving from cheaper cities. We also predicted that as people stayed in their new city they would get used to the new prices and would readjust their housing expenditures countering the initial impact of previous prices. We found support for both predictions in a sample of 928 movers from the PS…
A manifesto for reproducible science
Improving the reliability and efficiency of scientific research will increase the credibility of the published scientific literature and accelerate discovery. Here we argue for the adoption of measures to optimize key elements of the scientific process: methods, reporting and dissemination, reproducibility, evaluation and incentives. There is some evidence from both simulations and empirical studies supporting the likely effectiveness of these me…
Specification curve analysis
Friends of Victims: Personal Experience and Prosocial Behavior
Why do different people give to different causes? We show that the sympathy inherent to a close relationship with a victim extends to other victims suffering from the same misfortunes that have afflicted their friends and loved ones. Both sympathy and donations are greater among those related to a victim, and they are greater among those in a communal relationship as compared to those in an exchange relationship. Experiments that control for info…
Mistake: The Effect of Previously Encountered Prices on Current Housing Demand
Based on contrast effects studies from psychology, we predicted that movers arriving from more expensive cities would rent pricier apartments than those arriving from cheaper cities. We also predicted that as people stayed in their new city they would get used to the new prices and would readjust their housing expenditures countering the initial impact of previous prices. We found support for both predictions in a sample of 928 movers from the PS…
Weather To Go To College
Does current utility bias predictions of future utility for high stakes decisions? Here I provide field evidence consistent with such Projection Bias in one of life's most thought-about decisions: college enrolment. After arguing and documenting with survey evidence that cloudiness increases the appeal of academic activities, I analyse the enrolment decisions of 1,284 prospective students who visited a university known for its academic strengths …
Spurious? Name similarity effects (implicit egotism) in marriage, job, and moving decisions
Three articles published in the Journal of Personality and Social Psychology have shown that a disproportionate share of people choose spouses, places to live, and occupations with names similar to their own. These findings, interpreted as evidence of implicit egotism, are included in most modern social psychology textbooks and many university courses. The current article successfully replicates the original findings but shows that they are most …
Clouds make nerds look good: Field evidence of the impact of incidental factors on decision making
Abundant experimental research has documented that incidental primes and emotions are capable of influencing people's judgments and choices. This paper examines whether the influence of such incidental factors is large enough to be observable in the field, by analyzing 682 actual university admission decisions. As predicted, applicants' academic attributes are weighted more heavily on cloudier days and non‐academic attributes on sunnier days. The…
Stimulus sampling reimagined: Designing experiments with mix-and-match, analyzing results with stimulus plots
Stimuli selection in psychology experiments is typically unsystematic, undocumented, and irreproducible. This makes confounds likely to arise. The statistical analysis of psychology experiments with multiple stimuli, in turn, is typically reported at the aggregate level, averaging across stimuli. This makes confounds unlikely to be detected. Here, we propose changing both the design and analysis of psychology experiments. We introduce "Mix-and-Ma…
In defense of diligence: A rejoinder to Pelham and Carvallo (2011)
In Simonsohn (2011) I reported the results from 14 studies that suggest all existing evidence of implicit egotism in marriage, job, and location decisions is spurious. Lack of diligence by Pelham and colleagues explains in great part why the confounds behind their findings were not addressed in time. They almost never included controls, were dismissive of blatant alternative explanations, and on occasion misreported factual information that made …
New Yorkers Commute More Everywhere: Contrast Effects in the Field
Previous experimental research has shown that people's decisions can be influenced by options they have encountered in the past. This paper uses PSID data to study this phenomenon in the field, by observing how long people commute after moving between cities. It is found, as predicted, that (i) people choose longer commutes in a city they have just moved to, the longer the average commute was in the city they came from and (ii) when they move aga…
New Yorkers Commute More Everywhere: Contrast Effects in the Field
Previous experimental research has shown that people's decisions can be influenced by options they have encountered in the past. This paper uses PSID data to study this phenomenon in the field, by observing how long people commute after moving between cities. It is found, as predicted, that (i) people choose longer commutes in a city they have just moved to, the longer the average commute was in the city they came from, and (ii) when they move ag…
Clouds make nerds look good: Field evidence of the impact of incidental factors on decision making
Abundant experimental research has documented that incidental primes and emotions are capable of influencing people's judgments and choices. This paper examines whether the influence of such incidental factors is large enough to be observable in the field, by analyzing 682 actual university admission decisions. As predicted, applicants' academic attributes are weighted more heavily on cloudier days and non‐academic attributes on sunnier days. The…
Mistake: The Effect of Previously Encountered Prices on Current Housing Demand
Based on contrast effects studies from psychology, we predicted that movers arriving from more expensive cities would rent pricier apartments than those arriving from cheaper cities. We also predicted that as people stayed in their new city they would get used to the new prices and would readjust their housing expenditures countering the initial impact of previous prices. We found support for both predictions in a sample of 928 movers from the PS…
Friends of Victims: Personal Experience and Prosocial Behavior
Why do different people give to different causes? We show that the sympathy inherent to a close relationship with a victim extends to other victims suffering from the same misfortunes that have afflicted their friends and loved ones. Both sympathy and donations are greater among those related to a victim, and they are greater among those in a communal relationship as compared to those in an exchange relationship. Experiments that control for info…
Weather To Go To College
Does current utility bias predictions of future utility for high stakes decisions? Here I provide field evidence consistent with such Projection Bias in one of life's most thought-about decisions: college enrolment. After arguing and documenting with survey evidence that cloudiness increases the appeal of academic activities, I analyse the enrolment decisions of 1,284 prospective students who visited a university known for its academic strengths …
False-Positive Psychology: Undisclosed Flexibility in Data Collection and Analysis Allows Presenting Anything as Significant
In this article, we accomplish two things. First, we show that despite empirical psychologists’ nominal endorsement of a low rate of false-positive findings (≤ .05), flexibility in data collection, analysis, and reporting dramatically increases actual false-positive rates. In many cases, a researcher is more likely to falsely find evidence that an effect exists than to correctly find evidence that it does not. We present computer simulations and …
In defense of diligence: A rejoinder to Pelham and Carvallo (2011)
In Simonsohn (2011) I reported the results from 14 studies that suggest all existing evidence of implicit egotism in marriage, job, and location decisions is spurious. Lack of diligence by Pelham and colleagues explains in great part why the confounds behind their findings were not addressed in time. They almost never included controls, were dismissive of blatant alternative explanations, and on occasion misreported factual information that made …
Spurious? Name similarity effects (implicit egotism) in marriage, job, and moving decisions
Three articles published in the Journal of Personality and Social Psychology have shown that a disproportionate share of people choose spouses, places to live, and occupations with names similar to their own. These findings, interpreted as evidence of implicit egotism, are included in most modern social psychology textbooks and many university courses. The current article successfully replicates the original findings but shows that they are most …
A 21 Word Solution
Life after P-Hacking
Promoting Transparency in Social Science Research
Social scientists should adopt higher transparency standards to improve the quality and credibility of research.
P-curve: A key to the file-drawer.
Because scientists tend to report only studies (publication bias) or analyses (p-hacking) that "work," readers must ask, "Are these effects true, or do they merely reflect selective reporting?" We introduce p-curve as a way to answer this question. P-curve is the distribution of statistically significant p values for a set of studies (ps < .05). Because only true effects are expected to generate right-skewed p-curves-containing more low (.01s) th…
P -Curve and Effect Size: Correcting for Publication Bias Using Only Significant Results
Journals tend to publish only statistically significant evidence, creating a scientific record that markedly overstates the size of effects. We provide a new tool that corrects for this bias without requiring access to nonsignificant results. It capitalizes on the fact that the distribution of significant p values, p-curve, is a function of the true underlying effect. Researchers armed only with sample sizes and test results of the published find…
Small Telescopes: Detectability and the Evaluation of Replication Results
This article introduces a new approach for evaluating replication results. It combines effect-size estimation with hypothesis testing, assessing the extent to which the replication results are consistent with an effect size big enough to have been detectable in the original study. The approach is demonstrated by examining replications of three well-known findings. Its benefits include the following: (a) differentiating “unsuccessful” replication …
Promoting an open research culture
Author guidelines for journals could help to promote transparency, openness, and reproducibility
A manifesto for reproducible science
Improving the reliability and efficiency of scientific research will increase the credibility of the published scientific literature and accelerate discovery. Here we argue for the adoption of measures to optimize key elements of the scientific process: methods, reporting and dissemination, reproducibility, evaluation and incentives. There is some evidence from both simulations and empirical studies supporting the likely effectiveness of these me…
Psychology's Renaissance
In 2010–2012, a few largely coincidental events led experimental psychologists to realize that their approach to collecting, analyzing, and reporting data made it too easy to publish false-positive findings. This sparked a period of methodological reflection that we review here and call Psychology's Renaissance. We begin by describing how psychologists’ concerns with publication bias shifted from worrying about file-drawered studies to worrying a…
Two Lines: A Valid Alternative to the Invalid Testing of U-Shaped Relationships With Quadratic Regressions
Many psychological theories predict U-shaped relationships: The effect of x is positive for low values of x, but negative for high values, or vice versa. Despite implying merely a change of sign, hypotheses about U-shaped functions are tested almost exclusively via quadratic regressions, an approach that imposes an arbitrary functional-form assumption that in some scenarios can lead to a 100% rate of false positives (e.g., the incorrect conclusio…
Specification curve analysis
Stimulus sampling reimagined: Designing experiments with mix-and-match, analyzing results with stimulus plots
Stimuli selection in psychology experiments is typically unsystematic, undocumented, and irreproducible. This makes confounds likely to arise. The statistical analysis of psychology experiments with multiple stimuli, in turn, is typically reported at the aggregate level, averaging across stimuli. This makes confounds unlikely to be detected. Here, we propose changing both the design and analysis of psychology experiments. We introduce "Mix-and-Ma…
Computer Science (16 works) · Psychology (11 works) · Mathematics (8 works) · Social Psychology (8 works) · Decision-Making and Behavioral Economics (7 works) · Meta-analysis and systematic reviews (7 works) · Statistics (6 works) · Computer security (5 works) · Political science (5 works) · Economic and Environmental Valuation (4 works)