Statistical significance is a good measure of how sure we are there is a correlation, or in this case with an RCT, causation. But any layperson can look at a 3%

Statistical significance is a good measure of how sure we are there is a correlation, or in this case with an RCT, causation. But any layperson can look at a 3% effect and conclude, yeah, that's probably not that big of a deal. Or not, depending upon your preferences! No judgement. It's not something that requires a degree to determine, just an assessment of one's own values and the effect size in that context.