You can smoke this study
Friday posts are about the weird and wonderful side of econ research and the studies that are so clearly wrong that you wonder how anyone ever thought it would be a good idea to post them online.
This article examines a questionable economic study conducted by Evangelos Vasileiou of the Hellenic Mediterranean University in Greece, published in 2026. Vasileiou sought to uncover a market anomaly related to psychological stress on "No Smoking Day" in the UK, a day when smokers are encouraged to abstain from cigarettes for the day.
Vasileiou compared the performance of the FTSE 100 stock market on "No Smoking Wednesdays" to that of regular Wednesdays, finding a significant difference in returns. However, the statistical significance of this difference was only at the 10% level, which is considered weak. To improve the statistical significance, Vasileiou added control variables such as the proportion of smokers in the UK, the proportion of smokers who quit, and the proportion of people who own shares directly.
Adding these variables, which are correlated and show trends over time, significantly increased the statistical difference in returns, bringing it to the 5% level - a more acceptable threshold for publication. This manipulation of data and control variables highlights the questionable methodology used in Vasileiou's study, raising doubts about the validity of his findings.
Written by urgent.news from Klement on Investing's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
