This type of modeling must begin with empirical observations; this this a challenging and time consuming process but it is the only way of understanding inefficiencies. It is a complex study which will include substantial interviews and should be based on what participants believe as inefficiencies. With regard to "lack of information" you need to understand "known" and "unknown" (explicit and implicit) information. It is all too easy to "assume that" but that approach will not get to the core of the issue. 

I wish you well on this project but want to you appreciate that it will be more complex than you think and it will take longer than you think but worth the effort.

Good contributions are here.

Thanks all