TY - CHAP M1 - Book, Section TI - Critical Appraisal of Trauma Research A1 - Sauaia, Angela A1 - Moore, Ernest E. A2 - Feliciano, David V. A2 - Mattox, Kenneth L. A2 - Moore, Ernest E. PY - 2020 T2 - Trauma, 9e AB - KEY POINTSBy randomly distributing patients to the study groups, the potential risk factors in randomized clinical trials are likely to be evenly dispersed.Bayesian statistics are an approach for learning from evidence as it accumulates; that is, the Bayes theorem is applied to combine prior information with current information on an outcome of interest and derive a probability.The propensity score is the probability of treatment assignment conditional on observed baseline characteristics; that is, each treated patient is matched to one or more control patients with similar propensity scores.Relative risk or risk ratio (RR) compares the outcome probability in two groups (ie, with and without an intervention, or with and without a risk factor). When the RR is equal to 1, there is no evidence of effect.Odds ratios are good estimates of the RR when the outcome is relatively rare (<20%); however, this is not true when the outcome is more common.P value is the probability of obtaining the observed effect (or larger) under the null hypothesis that there is no effect; that is, the P value can be interpreted colloquially as the probability that the finding was the result of chance.Bias is the deviation of results due to systematic errors in the research methods and includes selection bias (study groups differ systematically) or observer/information bias (systematic differences in the way information is collected). SN - PB - McGraw Hill CY - New York, NY Y2 - 2024/10/12 UR - accesssurgery.mhmedical.com/content.aspx?aid=1175130644 ER -