Although the time to completion seems quite disparate between Europe and US, the difference isn't nearly as stark as it appears. Nearly all Europeans enter PhD

Although the time to completion seems quite disparate between Europe and US, the difference isn't nearly as stark as it appears. Nearly all Europeans enter PhD programs with a Master's degree in hand. At least in psychology (my discipline), US PhD programs will admit candidates directly from undergraduate. The overall time from bachelor's to PhD is similar when you account for these differences.