What are p values and how are p values used in clinical decision making?
What are p values? P values are measurements of probability due to chance. P values are also measurements of statistical significance, based on an arbitrary reference point of 0.05, or 1 in 20. Data sets with p values less than 0.05 are statistically significant, and those with p values greater than 0.05 are not. It is important to recognize that p values can dismiss chance, but cannot directly prove effect. A small p value (statistically significant) allows the physician to dismiss chance as a possibility when comparing two drugs. A large p value (statistically insignificant) does not allow the physician to dismiss any possibilities (chance, actual effect, confounding factors) when comparing two drugs. A large p value can be favorable in demonstrating a lack of difference in side effects between a drug and placebo. Factors determining p values When comparing the effects of two conditions (for example, placebo versus drug or drug versus drug), the p value is determined by the study des
