Aaron T. Beck
Beck also developed self-report measures of depression and anxiety including Beck Depression Inventory (BDI), Beck Hopelessness Scale, Beck Scale for Suicidal Ideation (BSS), Beck Anxiety Inventory (BAI), and Beck Youth Inventories. Beck is known for his research in psychotherapy, psychopathology, suicide, and psychometrics, which led to his creation of cognitive therapy and the BDI, one of the most widely used instruments for measuring depression severity.