Nor is it always simple to estimate the magnitude of effects, associations, risks, and costs based on the limited information given. The certainty of uncertainty. We can only say, here's what we know today. Tomorrow we may discover something quite different. The role of probability.
Probability is just an estimate of what is likely to happen, based on the available evidence.
The power of large numbers. In statistics, power refers to the probability of finding an effect if one exists. A larger sample size confers greater statistical power. In general, a sample of one makes a story, not a study. The danger of bias.