The Truthful Art: Data, Charts, and Maps for Communication

11. Uncertainty and Significance

Quantitative knowing is dependent on qualitative knowledge (...) In quantitative data analysis, numbers map onto aspects of reality. Numbers themselves are meaningless unless the data analyst understands the mapping process and the nexus of theory and categorization in which objects under study are conceptualized.

—John T. Behrens, “Principles and Procedures of Exploratory Data Analysis”

“Catalan public opinion swings toward ‘no’ for independence, says survey,” read the December 19, 2014, headline of the Spanish newspaper El País.¹ Catalonia has always been a region where national sentiments run strong, but independentism hadn’t been a critical issue for the Spanish government in Madrid until the last quarter ...