PD model validation Framework

[d.koutsomito]

Hi,

I was recently assigned a task on PD models validation framework. I have done my research and so far I came across various documents but I consider the most useful the following:

• BIS working paper no.14 (http://www.bundesbank.de/Redaktion/...nal_rating_systems.pdf?__blob=publicationFile)
  
• Internal Rating Based approaches from PRA (http://www.bankofengland.co.uk/pra/Documents/publications/ss/2013/ss1113.pdf)

The first one includes statistical test used for validation and also qualitative checks on the data used to develop the model. However, since it was last revised in 2005 I was wondering whether there is a more recent and robust document which can provide me with a deeper insight about the characteristics that a consistent validation framework should have.

Thanks.