The Beck Depression Inventory created by Aaron T. Beck, is a 21-question multiple-choice self-report inventory, one of the most widely used psychometric tests for measuring the severity of depression.
Historically, depression was described in psychodynamic terms as "inverted hostility against the self". The BDI was developed by collating patients' verbatim descriptions of their symptoms and then using these to structure a scale which could reflect the intensity or severity of a given symptom.
It contains 21 questions, each answer being scored on a scale value of 0 to 3. Higher total scores indicate more severe depressive symptoms.