Table 1.

Performance of machine learning classifiers for predicting gun ownership and gender.

Measure and data set (purpose)		Best classifier: accuracy	Best classifier: F1-score
Gun ownership
	Linked survey or Twitter sample (cross-validation average)	0.72	0.69
	Holdout from linked survey or Twitter sample (internal validation)	0.71	0.70
	Gun conversation sample (external validation)	0.65	0.64
Gender
	Gender sample (training)	0.90	0.87
	Holdout from gender sample (internal validation)	0.90	0.88
	Linked survey or Twitter sample (external validation)	0.74	0.73