Prison works. - Are they sure?

http://www.dailymail.co.uk/news/article-1385479/Criminals-spend-longer-bars-likely-reoffend.html

Surely this cannot be right. It flies in the face of 60 years of liberal/left experimentation with the fabric and nature of our society. Moreover, the left are never wrong at least that is what they claim when trying to stifle debate and undemocratically impose their will onto the populace!