Table 1.

A two-by-two contingency table for analysis.

	With an adverse event of interest	Without an adverse event of interest	Total
With a drug of interest	n11	n10	n11+n10
Without a drug of interest	n01	n00	n01+n00
Total	n11+n01	n10+n00	n11+n10+n01+n00

n11: the number of co-occurrences of interest. n11+n10: the total number of co-occurrences with a drug of interest. n11+n01: the total number of co-occurrences with an adverse event of interest. n11+n10+n01+n00: the total number of co-occurrences in the database.