The Short Version
This claim is well-supported. Major health authorities — including the NHS, WHO, Mayo Clinic, APA, and the Australian Psychological Society — all independently identify exposure therapy as one of the most effective and best-evidenced treatments for phobias. Mayo Clinic calls it "the best treatment" for specific phobias, and the Australian Psychological Society notes it has "the most research evidence." The claim's careful phrasing ("considered one of the most effective") accurately reflects the established clinical consensus.