Table 2. Frequency of description of design elements and design element options in the two preclinical datasets evaluated (CAMARADES (brain trauma/stroke) and toxicology).

Design element	Element options	CAMARADES N = 100	Toxicology N = 100
Control group	None	0	0
	Concurrent	98	92
	Historic	0	0
	Unclear	2	8
Unit of concern	Group	0	12
	Individual	92	37
	Nested	0	17
	Unclear	8	34
Arrangement of the factors	Complete factorial	27	42
	Cross-over	0	0
	Incomplete factorial	12	11
	Parallel	58	24
	Split-Plot	0	20
	Unclear	3	3
Allocation	Haphazard	0	0
	Minimization	0	0
	Random	79	62
	Systematic	0	0
	Unclear	21	38
Concealment (a)	Intervention allocation	12	0
	NDD*	88	100
Concealment (b)	Outcome assessment	60	12
	NDD*	40	88
Independence (a)	Pseudo-replication	44	50
	NDD*	56	50
Independence (b)	Repeated measures	40	59
	NDD*	60	41
Investigator-identified study design	Provided	0	7
	NDD*	100	93
Nature of the factors	All could be randomized	94	69
	Some could be randomized	5	30
	None could be randomized	0	0
	Unclear	1	1

* NDD = no discernable description: neither reviewer/reader was able to find text that described this element.