About Objective Function-OF (PBIAS and NSE)

[Javier Fernando Mendez Monroy]

Good morning.

I am evaluating the OF equation for my data. 

This equation is expressed as OF=√(〖(1-NSE)〗^2+〖(|PBIAS|+0.5)〗^2 ) (Wang, Yen, Liu, & Liu, 2014).

So, my question is if PBIAS must be assessed in percentage or as a number (e g, percentage=100% or number=1). 

And, in a perfect fit model, NSE=1 and PBIAS=0, so OF optimum should be 0.5?

Thanks for your help.

[Jaehak]

In the formula you referred to, PBIAS is used as a fraction. In a perfect fit, the OF=0.25.