00443nas a2200157   4500000000100000008004100001100001400042700001600056700001500072700001400087700001300101245014300114300001500257490000700272050000600279       2008                            d1 aMacedo L.1 aHerbert Rob1 aMcAuley J.1 aKamper S.1 aMaher C.00aTrial methodology and patient characteristics do not influence the size of placebo effects on pain. Meta-regression of trial-level factors  a256-260.  0 v61  aY