An effect size estimates the magnitude of the difference between two means/medians.
The term effect size relates to both unstandardized measures (for example, the difference between group means) and standardized measures (such as Cohen's d; the standardized difference between group means). Standardized measures are more appropriate than unstandardized measures when the metrics of the variables do not have intrinsic meaning, when combining results from multiple studies, or when comparing results from studies with different measurement scales.
A point estimate is a single value that is the best estimate of the true unknown parameter; a confidence interval is a range of values and indicates the uncertainty of the estimate.
