Table 3

Application of the procedures to counter-balance some common research malpractices

	ALL		Answer		No answer		p Value
	N	Per cent	N	Per cent	N	Per cent
Number of systematic reviews	118	100	80	68	38	32
Search of unpublished trials and/or test for publication bias							0.914
Publication bias discussed only or not mentioned	39	33	26	33	13	34
Unpublished trials searched OR publication bias tested	56	47	39	49	17	45
Unpublished trials searched AND publication bias tested	23	19	15	19	8	21
Contact with authors of the studies							0.427
Study authors not contacted	45	38	28	35	17	45
Study authors contacted for method or unspecified reason	15	13	12	15	3	8
Study authors contacted for unreported outcomes	58	49	40	50	18	47
Duplicate publications							0.057
Not searched or not mentioned	37	31	21	26	16	42
Searched and found, not referenced OR no mention of results	71	60	54	68	17	45
Searched, found and referenced	10	8	5	6	5	13
Sponsors of the studies							0.809
Not mentioned	91	77	63	79	28	74
Information extracted	21	18	13	16	8	21
Information extracted and subgroup analyses performed	6	5	4	5	2	5
Conflicts of interests of study authors							0.703
Not mentioned	113	96	77	96	36	95
Information extracted	5	4	3	4	2	5
Information extracted and subgroup analyses performed	0	0	0	0	0	0
Ethical approval of included studies							0.481
Not mentioned	115	97	77	96	38	100
Information extracted	3	3	3	4	0	0
Information extracted and subgroup analyses performed	0	0	0	0	0	0
Number of procedures applied							0.403
None	11	9	6	8	5	13
1 or 2 procedures	48	41	34	43	14	37
3 or 4 procedures	56	47	38	48	18	47
5 procedures	3	3	2	3	1	3
Median (IQR)	2.5 (1–3)		2.5 (2–3)		2.5 (1–3)
Explicit mention of misconduct by reviewers							0.296
No, or not mentioned	111	94	74	93	37	97
Yes	7	6	6	8	1	3

Answer: reviews in which extracted data were confirmed by reviewers. No answer: reviews in which extracted data were not confirmed by reviewers. p Value testing the null hypothesis of equal distribution between the reviews for which the authors responded to our inquiry and those who did not (χ² test). Percentages may not add-up to 100% because of rounding errors.