Table 12. Number of studies reporting the study hypothesis, three animal characteristics and the number of animals used.

Species	Characteristics†	Hypothesis clearly stated	Animal numbers Not reported	Reported
Mouse	No	No	0	3
		Yes	3	28
	Yes	No	1	2
		Yes	2	33
Primate	No	No	0	5
		Yes	0	40
	Yes	No	0	1
		Yes	0	40
Rat	No	No	0	0
		Yes	2	20
	Yes	No	0	1
		Yes	4	86
All	No	No	0	8
		Yes	5	88
	Yes	No	1	4
		Yes	6	159*

^†Sex, strain and either weight or age.

^*59% (159/271) of all papers clearly stated the study hypothesis, reported three animal characteristics (sex, strain and weight or age), and also reported the number of animals used.