Learn in the textbookRegression, Correlation, and Spurious Correlation
DefinitionA spurious correlation (擬似相関) is when two quantities with no direct causal link appear correlated because a third factor (第三の要因) affects both of them.
ExplanationThe third factor is also called a confounding factor (交絡因子), and because the two quantities move together whenever it changes, the data can show a strong correlation. Since changing one of them leaves the other unchanged, a measure chosen on the strength of the correlation alone will have no effect.
AnalogyIn summer, electric fans and shaved ice both sell well, but the shaved ice is not selling the fans; the heat is driving both.
Memory hookThe first character of 擬似相関 means "imitating", the same one used for onomatopoeia (擬音), and the English word spurious likewise means "false".