Paul F. Lazarsfeld’s “The Psychological Aspect of Market Research” (originally published in Harvard Business Review, 1934) investigates the integration of psychological procedures in market research, emphasizing two primary contributions: interpretative analysis of market data and structural examination of the purchase act. Drawing from several empirical studies, Lazarsfeld demonstrates how psychological interpretation—particularly through comparative statistical analyses of consumer motives and reasons—enables deeper understanding of consumer attitudes, the confidence problem in purchasing, and effective market interventions. The paper advocates for broad, methodologically diverse data collection practices in market surveys, outlining general rules for questioning and interpreting responses. Lazarsfeld distinguishes between individual purchase motives as interpreted by researchers and the subjective reasons reported by respondents, arguing for their complementary roles in developing sound marketing strategies. The paper concludes with a call for greater collaboration between psychologists and market researchers to further refine the logic, reliability, and theoretical foundations of psychological market analysis.