GUILLERMO M ACBETH’s scientific contributions

Effect size (ES) is a necessary complement to the statistical hypothesis testing, however, researchers rarely report ES in their papers. This work provides a conceptual review of the ES estimates for the difference between two means, taking into account the most important algorithms and their interpretation. We also provide a guide to the freely available and easy-to- use ViSta statistical software to compute ES. We hope this paper contributes to the diffusion of ES methods and encourages its use among researchers in Psychology.

The calibration or confidence is broadly defined as the relation of correspondence or discrepancy between the subjective estimation of success and the actual success in a series of tasks. The underconfidence bias is defined as underestimation and the overconfidence bias as overestimation. Underconfidence and overconfidence biases are presented as cognitive phenomena. The main debiasing methods are analyzed. Two debiasing strategies are identified. The methodological strategy is differentiated from the cognitive strategy. An experiment that dissolves the underconfidence bias in verbal tasks through a simple training is presented and analyzed. It is suggested that the dissolution is due to training in calibration rather than training in the experimental task. The effect of adjustment in calibration is explained by the adaptive participation of metacognitive processing.