Astrology captivates millions, yet when it comes to rigorous testing, even the most intuitively appealing claims deserve a clear-eyed appraisal. A recent Clearer Thinking analysis1 —involving 308 online volunteers, 12 sun-sign categories, and 37 life-outcome measures—reports essentially zero predictive power for sun-sign astrology. That headline is hard to argue with, but a closer look at their methods reveals opportunities for more balanced, informative studies.
- Sampling and Scope. The study’s convenience sample of self-selected adults skews demographics and limits generalizability. Likewise, reducing astrology to sun-sign dummies overlooks richer natal-chart variables (planetary positions, aspects) that some practitioners argue carry most interpretive weight. A null result for one slice of astrology does not rule out subtle effects elsewhere.
- Outcome Choices and Statistical Power Testing. 37 disparate outcomes—from income to mental health—dilutes focus and strains statistical power. Without a priori hypotheses linking specific birth-date features to particular life domains, many real but small effects could slip under the radar. A formal power analysis, or narrowing to theoretically grounded outcomes, would sharpen the inquiry.
- Multiple Comparisons and Model Transparency. Running dozens of regressions without correcting for family-wise error inflates false-positive risk and undermines confidence in both hits and misses. The use of ridge regression is promising, but the study’s omission of tuning details and covariate controls (age, gender, seasonality) leaves open questions about under- or over-regularization.
- Beyond Sun Signs: Toward Rigorous Astrology Research. A more balanced research agenda would preregister a limited set of outcomes, power studies to detect small effects, and include richer astrological variables. Controlling for demographic and temporal confounders—plus proper multiple-testing adjustments—would transform astrology’s examination from scattershot to scientifically robust.
Astrology tests will always provoke debate. By tightening sampling, clarifying hypotheses, and committing to transparent analytics, we can move beyond simple debunking toward research that genuinely probes whether—and under what conditions—astrology might offer any predictive insight. That kind of rigor serves both skeptics and curious seekers alike.
1 Clearer Thinking Team (2024, Jan. 10). Can astrological sun signs (or zodiac signs) predict facts about people's lives? We tested it. https://www.clearerthinking.org/post/we-tested-the-predictive-power-of-astrology-here-are-the-results
