Table 2.

Statistics comparing BioCreative II gene normalization task (human) with BioCreative I tasks (mouse, fly, and yeast).

	Number of unique IDs	Average synonym length in words	Average synonyms per identifier	Average identifiers per synonym (ambiguity)	BioCreative maximum recall @ precision	BioCreative maximum F-measure
Human	32,975	2.17	5.55	1.12	0.88 @ 0.50	0.81
Mouse	52,494	2.77	2.48	1.02	0.90 @ 0.43	0.79
Yeast	7,928	1.00	1.86	1.01	0.96 @ 0.65	0.92
Fly	27,749	1.47	2.94	1.09	0.84 @ 0.73	0.82

Statistics on synonyms are based on lexical resources provided by the task organizers.