Condition beneath study; `placebo' needles, which include the Streitberger needle , which appear to penetrate the skin but which don't do so; strategies,Vickers et al.Trials , : www.trialsjournal.comcontentPage ofTable Examples of adequate and inadequate allocation concealmentAdequate allocation conceal.Situation under study; `placebo' needles, for example the Streitberger needle , which appear