Hello 

On PMBOK Fifth Edition Page 158, there is example of lag.

Activity 1 (Preceding activity) = Write Draft

Activity 2 (Successor activity)= Edit Draft

Activity 1 is connected to Activity 2 by Start to Start with 15 Days Lag

 

Now I am not understanding, why PMBOK has mentioned SS - 15 Days (Lag).

Why PMBOK has not mentioned SS + 15 Days (Lag)

 

Please explain this.

Thanks