Analysis of 285,000 Transactions Reveals Fraud Peaks at 2AM, Not 11AM

A data analyst examined the widely used Kaggle Credit Card Fraud Detection dataset, comprising 284,807 anonymized European transactions from September 2013, of which only 492 — just 0.173% — were fraudulent. The analysis found that fraudulent transactions tend to cluster at low amounts, rarely exceeding a few hundred dollars, suggesting fraudsters deliberately avoid large sums that trigger alerts. An initial hour-by-hour breakdown appeared to show fraud spiking at both 2AM and 11AM based on raw case counts, but recalculating by fraud rate per transaction volume told a different story. Hour 2 proved a genuine high-risk window at a 1.71% fraud rate — roughly 10 times the dataset average — while Hour 11's apparent spike largely reflected higher transaction volume rather than elevated risk. The project highlights a key analytical pitfall: raw counts can be misleading without normalization, a principle the analyst compared to reviewing financial margins without examining both numerator and denominator.