Many times, you need to prove to your customer and business
people the value of adopting Agile mindset, methods and practices. The
following resource are very valuable in this regard:

1) The Business Value of Agile Software Methods by David Rico; Saya Sone; Hasan Sayani Published by J. Ross Publishing, 2009

This book has useful info on business value and return on investment of Agile methods and practices.

2) There is a report named “2015 State of Agile
Development” from CEB (Corporate Executive Board) Applications
Leadership Council. 

From ahm507.blogspot.com