A method for determining an intervention effect index for a person executing a task is provided and comprises: obtaining sensing information by at least one sensor coupled to the person, the sensing information includes first sensing information relating to performance in executing the task and second sensing information relating to an emotional state； determining, on the basis of said first sensing information, a performance value difference indicating a variation between performance in executing the task before and after an intervention is applied, the intervention representing an excitation affecting the person； estimating, on the basis of said second sensing information, an emotional value difference indicative of a variation between emotional states before and after the intervention is applied； determining the intervention effect index on the basis of said performance value difference and said emotional value difference, the intervention effect index representing an indication on effectiveness of the intervention on the person.
