For the first time in the Turner Prize history an architectural practices' work is considered art, and hence Assemble is nomiated this year.
"Assemble have never claimed to be artists – and their shortlisting has no doubt raised some eyebrows in the rarified realms of the gallery world – but in both their approach to materials and the collaborative process by which their projects are made, their work transcends the norms of conventional architectural practice."Oliver Wainwright

"It’s not quite a pickled calf – but the rebirth of a troubled Toxteth community might be art. The story of the street and the young architects succeeding where every official plan has failed has caught the art world’s attention" Oliver Wainwright
more on this story at: http://www.theguardian.com/artanddesign/architecture-design-blog/2015/may/12/assemble-turner-prize-2015-wildcard-how-the-young-architecture-crew-assemble-rocked-the-art-world
Other nominees for this year include:
Bonnie Camplin
Janice Kerbel
Nicole Wermers