In ABC analysis used in Rational Emotive therapy as proposed by Albert Ellis, ABC refers to :

antecedent - belief - consequence

Albert Ellis formulated the Rational Emotive Therapy (RET). The central thesis of this therapy is that irrational beliefs mediate between the antecedent events and their consequences. The first step in RET is the antecedent-belief-consequence (ABC) analysis. Antecedent events, which caused the psychological distress, are noted. The client is also interviewed to find the irrational beliefs, which are distorting the present reality. Irrational beliefs may not be supported by empirical evidence in the environment. These beliefs are characterised by thoughts with ‘musts’ and ‘shoulds’, i.e. things ‘must’ and ‘should’ be in a particular manner. Examples of irrational beliefs are, “One should be loved by everybody all the time”, “Human misery is caused by external events over which one does not have any control”, etc. This distorted perception of the antecedent event due to the irrational belief leads to the consequence, i.e. negative emotions and behaviours. Irrational beliefs are assessed through questionnaires and interviews.