Normal Curves: Sexy Science, Serious Statistics

Epidemiology and Clinical Research Graduate Certificate Program

Programs that we teach in:

Epidemiology and Clinical Research Graduate Certificate Program

Find us on:

Kristin - LinkedIn & Twitter/X

Regina - LinkedIn & ReginaNuzzo.com

(00:00) - Intro
(04:36) - Did they have real research hypotheses?
(10:29) - Observational or randomized experiment?
(20:09) - PICOT and PIVOT
(26:20) - Memory problems
(32:03) - Five outcomes and measurement problems therein
(36:56) - SMART
(41:50) - Multiple Testing Dude is having a great time
(52:36) - How big is the effect?
(59:06) - Wrap-up and Irish Coffee rating scale

64 MIN

NOV 17, 2025

Holiday Survival Guide: How to talk about scientific studies around the dinner table

Does a little alcohol really make you speak a foreign language better? This week we unpack a quirky randomized trial that tested Dutch pronunciation after a modest buzz—and came to the opposite conclusion the researchers expected. We use it as the perfect holiday case study: instead of arguing with Uncle Joe at the dinner table, we’ll show you how to pull apart a scientific headline using a friendly, practical checklist anyone can learn. Along the way we stress-test the study’s claims, take a quick detour into what a .04% buzz actually looks like, and run our own before-and-after experiment with two brave science journalists at the ScienceWriters2025 conference in Chicago. A holiday survival guide with vodka tonics, statistical sleuthing, and a few surprisingly smooth French phrases.

Statistical topics

Alternative explanations
Arithmetic consistency / GRIM test
Blinding
Effect size / magnitude
Generalizability / external validity
Observational studies vs. experiments
Outcome measurement
PICOT framework
Placebo and expectancy effects
Primary outcomes / pre-specification
Randomized controlled trials
Research hypotheses
Sample size
SMART framework
Statistical significance (signal vs. noise)
Transparency and trustworthiness

Methodological morals

“You don't need a PhD to read a study. Just remember, PICOT and SMART.”
“A decimal point can mean the difference between life and death. Details matter.”

References

Renner F, Kersbergen I, Field M, Werthmann J. Dutch courage? Effects of acute alcohol consumption on self-ratings and observer ratings of foreign language skills. J Psychopharmacol. 2018;32(1):116-122. doi:10.1177/0269881117735687

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding

Epidemiology and Clinical Research Graduate Certificate Program

Programs that we teach in:

Epidemiology and Clinical Research Graduate Certificate Program

Find us on:

Kristin - LinkedIn & Twitter/X

Regina - LinkedIn & ReginaNuzzo.com

61 MIN

NOV 3, 2025

Shingles Shot and Dementia: Could one vaccine protect your brain?

What do chickenpox and shingles have to do with your brain? This week, we dig into two 2025 headline-grabbing studies that link the shingles shot to lower dementia rates. We start in Wales, where a birthday cutoff turned into the perfect natural experiment, and end in the U.S. with a multi-million-person megastudy. Featuring bias-variance Goldilockses, Fozzy-the-Bear regression discontinuities, a Barbie-versus-Oppenheimer showdown for propensity scores – and the hottest rebrand of inverse-probability weighting you’ll ever hear.

Statistical topics

Absolute vs. relative risk
Bias–variance tradeoff
Causal inference
Censoring
Confounding
Fuzzy regression discontinuity design
Healthy-user bias
Inverse probability of treatment weighting (IPTW)
Longitudinal study
Natural experiment
Negative controls
Optimal bandwidth
Propensity scores
Selection bias
Subgroup analysis
Triangular kernel weights

Methodological morals

“Propensity scores are the lipstick you put on observational pigs.”
“Natural experiments are a hot flirtation date with causality.”

References

Eyting M, Xie M, Michalik F, Heß S, Chung S, Geldsetzer P. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. 2025 May;641(8062):438-446. doi: 10.1038/s41586-025-08800-x. Epub 2025 Apr 2. PMID: 40175543; PMCID: PMC12058522.
Polisky V, Littmann M, Triastcyn A, et al. Varicella-zoster virus reactivation and the risk of dementia. Nat Med. Published online October 6, 2025. doi:10.1038/s41591-025-03972-5
Sainani KL. Propensity scores: uses and limitations. PM&R 2012; 4:693-97.

Detailed Show Notes Page

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding

Epidemiology and Clinical Research Graduate Certificate Program

Programs that we teach in:

Epidemiology and Clinical Research Graduate Certificate Program

Find us on:

Kristin - LinkedIn & Twitter/X

Regina - LinkedIn & ReginaNuzzo.com

(00:00) - Intro and first gratuitous mention of sex
(03:56) - What are shingles, chickenpox, and the vaccines against them?
(12:30) - Fun facts about the varicella zoster and herpes viruses
(18:00) - A natural experiment in Wales
(21:54) - What is the Goldilocks optimal bandwidth?
(26:17) - Fuzzy regression discontinuity design demystified
(32:43) - Shingles vaccine vs dementia showdown
(34:13) - Absolute risk reduction paradox
(37:44) - Effects for men and women differ
(41:07) - A giant longitudinal study
(47:51) - Propensity scores demystified via Barbie and Oppenheimer
(53:55) - Using propensity scores to make matches
(58:08) - Inverse probability of treatment weighting demystified via more Barbenheimer
(01:02:27) - Attempts to rename IPTW for TikTok
(01:05:59) - Longitudinal study results
(01:10:00) - Smooch ratings and methodological morals: pigs and hot dates

72 MIN

OCT 20, 2025

Scary Bridge Study: Can fear make you horny?

What if a haunted house makes your date look hotter? This week we dive into the infamous Scary Bridge Study — the 1970s classic that launched a thousand pop-psych takes on fear and lust. It’s the one with the swaying bridge, pretty “research assistant,” and phone number scrawled on torn paper. The study became legend, but how sturdy were its stats? We retrace the design, redo the numbers, and see how many math errors it takes to sway a suspension bridge. Along the way we find an erotic-fiction writing exercise, Adventure Dudes choosing their own experimental groups, and snarky replicators who tried (and failed) to make fear sexy again. We wrap with what the latest research says about when fear really does boost attraction — and when it backfires spectacularly. A Halloween story of danger, desire, and unconscious sexual drive.

This episode has a video version! https://www.youtube.com/watch?v=2coWoS_3460

Statistical topics

Arithmetic checks
Chi-square test
Confounders
GRIM test
Inter-rater reliability
Meta-analysis
Negative control
Randomization
Replication
Sample size
Signal vs. noise
Statistical sleuthing
Subjective measurement
T-test

Methodological morals

“Those who don't verify their numbers dig their own statistical graves.”
“Famous doesn't mean flawless.”

References

Brown, NJ, Heathers, JA. The GRIM test: A simple technique detects numerous anomalies in the reporting of results in psychology. Social Psychological and Personality Science. 2017; 8(4):363-369.
Dutton DG, Aron AP. Some evidence for heightened sexual attraction under conditions of high anxiety. J Pers Soc Psychol. 1974;30(4):510-517. doi:10.1037/h0037031
Foster CA, Witcher BS, Campbell WK, Green JD. Arousal and attraction: Evidence for automatic and controlled processes. J Pers Soc Psychol. 1998;74(1):86-101.
Kenrick DT, Cialdini R, Linder D. Misattribution under fear-producing circumstances: Four failures to replicate. Pers Soc Psychol Bull. 1979;5(3):329-334.
van der Zee T, Anaya J, Brown NJL. Statistical heartburn: an attempt to digest four pizza publications from the Cornell Food and Brand Lab. BMC Nutr. 2017;3:54. Published 2017 Jul 10. doi:10.1186/s40795-017-0167-x
http://www.prepubmed.org/grim_test/

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding

Epidemiology and Clinical Research Graduate Certificate Program

Programs that we teach in:

Epidemiology and Clinical Research Graduate Certificate Program

Find us on:

Kristin - LinkedIn & Twitter/X

Regina - LinkedIn & ReginaNuzzo.com

(00:00) - Intro: Fear and Flirtation on a Suspension Bridge
(05:40) - A Classic 1970s Experiment with No IRB to be Found
(11:15) - Adventure Dudes Choose Their Own Bridge
(17:00) - The Sexy Story Scale
(22:20) - Cool Factor and the Negative Control
(28:54) - Grim Reaper Math
(36:29) - T-Tests, Chi-Squares, and Shaky Results
(42:44) - Electric Shocks and Damsels in Distress
(50:49) - Replications and Rejections
(58:39) - Wrap-Up, Methodological Morals, and a New Sexy Rating Scale

64 MIN

OCT 6, 2025

Ultramarathons: Can vitamin D protect your bones?

Ultramarathoners push their bodies to the limit, but can a giant pre-race dose of vitamin D really keep their bones from breaking down? In this episode, we dig into a trial that tested this claim – and found a statistical endurance event of its own: six highly interchangeable papers sliced from one small study. Expect missing runners, recycled figures, and a peer-review that reads like stand-up comedy, plus a quick lesson in using degrees of freedom as your statistical breadcrumbs.

Statistical topics

Data cleaning and validation
Degrees of freedom
Exploratory vs confirmatory analysis
False positives and Type I error
Intention-to-treat principle
Multiple testing
Open data and transparency
P-hacking
Salami slicing
Parametric vs non-parametric tests
Peer review quality
Randomized controlled trials
Research reproducibility
Statistical sleuthing

Methodological morals

“Degrees of freedom are the breadcrumbs in statistical sleuthing. They reveal the sample size even when the authors do not.”
“Publishing the same study again and again with only the outcomes swapped is Mad Libs Science, better known as salami slicing.”

References

Boswell, Rachel. Pre-race vitamin D could do wonders for ultrarunners’ bone health, according to science. Runner’s World. September 25, 2025.
Mieszkowski J, Stankiewicz B, Kochanowicz A, et al. Ultra-Marathon-Induced Increase in Serum Levels of Vitamin D Metabolites: A Double-Blind Randomized Controlled Trial. Nutrients. 2020;12(12):3629. Published 2020 Nov 25. doi:10.3390/nu12123629
Mieszkowski J, Borkowska A, Stankiewicz B, et al. Single High-Dose Vitamin D Supplementation as an Approach for Reducing Ultramarathon-Induced Inflammation: A Double-Blind Randomized Controlled Trial. Nutrients. 2021;13(4):1280. Published 2021 Apr 13. doi:10.3390/nu13041280
Mieszkowski J, Brzezińska P, Stankiewicz B, et al. Direct Effects of Vitamin D Supplementation on Ultramarathon-Induced Changes in Kynurenine Metabolism. Nutrients. 2022;14(21):4485. Published 2022 Oct 25. doi:10.3390/nu14214485
Mieszkowski J, Brzezińska P, Stankiewicz B, et al. Vitamin D Supplementation Influences Ultramarathon-Induced Changes in Serum Amino Acid Levels, Tryptophan/Branched-Chain Amino Acid Ratio, and Arginine/Asymmetric Dimethylarginine Ratio. Nutrients. 2023;15(16):3536. Published 2023 Aug 11. doi:10.3390/nu15163536
Stankiewicz B, Mieszkowski J, Kochanowicz A, et al. Effect of Single High-Dose Vitamin D3 Supplementation on Post-Ultra Mountain Running Heart Damage and Iron Metabolism Changes: A Double-Blind Randomized Controlled Trial. Nutrients. 2024;16(15):2479. Published 2024 Jul 31. doi:10.3390/nu16152479
Stankiewicz B, Kochanowicz A, et al. Single high-dose vitamin D supplementation impacts ultramarathon-induced changes in serum levels of bone turnover markers: a double-blind randomized controlled trial. J Int Soc Sports Nutr. 2025 Dec;22(1):2561661. doi: 10.1080/15502783.2025.2561661.

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding