Table 3

Use of procedures in placebo groups of clinical and experimental studies

Procedure		% of studies that used each procedure
Procedure		Experimental (n=58)	Clinical (n=111)
Patient’s beliefs and characteristics
1.	Select intervention based on patient’s treatment history	55	75
2.	Create positive expectancy	76	5
3.	Reduce negative expectancy	3	0
4.	Convey a positive therapeutic message through informed consent procedures	43	1
5.	Harness sociocultural context	0	0
Practitioner’s beliefs and characteristics
6.	Practitioner expectancy	0	1
7.	Practitioner’s personal characteristics	9	0
Healthcare setting
8.	Active recruitment	14	16
9.	Active retention	3	2
10.	Follow-up	2	16
11.	Follow a standardised protocol	85	63
12.	Ethical oversight	78	69
13.	Participating in research	86	84
14.	Symptom monitoring	95	89
15.	Enhanced environment	5	0
Treatment characteristics
16.	Sham intervention—medication	71	55
17.	Sham interventions—physical	33	41
18.	Sham interventions—attention only	2	5
19.	Ineffective substances	0	1
20.	Use side effects	0	1
21.	Matched treatments	40	82
22.	Maximised treatment procedures	22	3
23.	Conditioning	41	0
Patient–practitioner interaction
24.	The process of informed consent	88	77
25.	Detailed history	19	33
26.	Diagnosis/tests	36	41
27.	Care	0	1
28.	Patient-centred communication	0	0
29.	Extra attention	2	63
30.	Continuity of care	7	14