E-values are a new tool that enables investigators to estimate the likelihood that some unmeasured confounder might overcome seemingly positive results. They are very easy to calculate and any reader of the medical literature can do this calculation to get a sense for how likely it is that there is some unmeasured factor in an observational study that might negate otherwise seemingly positive findings. Read the article: Using the E-Value to Assess the Potential Effect of Unmeasured Confounding in Observational Studies E-Value Calculator