Avista Capital Partners II SC 13G INC Research Holdings, Inc.

EXHIBIT 1

JOINT FILING AGREEMENT

We, the signatories of the Statement on Schedule 13G to which this Agreement is attached, hereby agree that such statement is, and any amendments thereto filed by any of us will be, filed on behalf of each of us. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original and all of which together shall constitute one instrument. Dated: February 11, 2015

AVISTA CAPITAL PARTNERS II GP, LLC
By:	/s/ David Burgstahler
Name:	David Burgstahler
Title:	Authorized Representative

AVISTA CAPITAL PARTNERS II, L.P.
By:	Avista Capital Partners II GP, LLC its General Partner
By:	/s/ David Burgstahler
Name:	David Burgstahler
Title:	Authorized Representative

AVISTA CAPITAL PARTNERS (OFFSHORE) II, L.P.
By:	Avista Capital Partners II GP, LLC its General Partner
By:	/s/ David Burgstahler
Name:	David Burgstahler
Title:	Authorized Representative

AVISTA CAPITAL PARTNERS (OFFSHORE) II-A, L.P.
By:	Avista Capital Partners II GP, LLC its General Partner
By:	/s/ David Burgstahler
Name:	David Burgstahler
Title:	Authorized Representative

ACP INC RESEARCH CO-INVEST, LLC
By:	Avista Capital Partners II GP, LLC its manager
By:	/s/ David Burgstahler
Name:	David Burgstahler
Title:	Authorized Representative

INC RESEARCH MEZZANINE CO-INVEST, LLC
By:	Avista Capital Partners II GP, LLC its manager
By:	/s/ David Burgstahler
Name:	David Burgstahler
Title:	Authorized Representative