The Sydney Morning Herald reports:
British scientists found that while carrying a charm had no impact on events based on chance, such as winning the lottery, those who believed in them felt more confident and optimistic. ... [A]lthough sceptical of any magical effects, these people felt more confident, secure and optimistic about the future, the survey found. ... Perhaps the most compelling statistic came at the end of the survey when participants were told they could give up the lucky coin -- 70 per cent said they would keep carrying it.
That the "lucky" coins made people feel more lucky and confident should not be underestimated in its importance. These things probably gave people the feeling of a little bit more "control" over their fates - it gave them an "edge" against random events. It's a fact of human psychology that when people feel more "in control" of their lives, they suffer from less depression and fewer health problems. That, in turn, is likely to help them do better overall. A lucky charm won't improve your "luck," but it if gives you a psychological boost which, in turn, helps in your life, does that mean that the charm "worked"? What's the difference between that and a sugar pill that "works"?