Melchart 2005.

Methods	Design: three group parallel trial Purpose: study the effect of acupuncture on tension type headache
Participants	Patients: out‐patients with tension type headache Baseline comparability: yes for most aspects, however 'some differences in previous use of acupuncture and in parts of the pain questionnaire'.
Interventions	Placebo: needling at places not regarded true acupuncture sites Untreated: no needling Experimental: needling at places regarded true acupuncture sites (Co‐intervention: standard headache treatment)
Outcomes	Days with headache Hours with headache Headache scores Days with more than mild headache Days with analgesic drugs Number of days with medication Pain disability index SF‐36 Algemeine Depressionskala Scale for assessing the emotional aspects of pain Average pain (1 to 10 scale)
Notes	Average days with analgesic drugs in placebo group was 2.6 (SD: 2.6), and in the no‐treatment group 4.4 (SD: 4.1) at week 12.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	'random list generated with sample size 2.0 by the statistician'
Allocation concealment?	Low risk	'centralized telephone randomization procedure'
Blinding? Treatment provider	High risk	Not described as double‐blind (placebo/acupuncture)
Blinding? Outcome assessor	Unclear risk	Not relevant as patient reported outcome
Incomplete outcome data addressed? All outcomes	Low risk	Drop‐out < 15%
Free of selective reporting?	Low risk	Primary outcome specified in protocol
Free of other bias?	Unclear risk	Average days with analgesic drugs in placebo group was 2.6 (SD: 2.6), and in the no‐treatment group 4.4 (SD:4.1).
No signs of variance inequality or skewness?	High risk	Either variance inequality (F‐test statistically significant) or skewness (1.64 standard deviations exceeds the mean)
Trial size > 49?	Low risk	N = 120
Clearly concealed allocation + trial size > 49 + drop‐out max 15%	Low risk	All three categories fulfilled