The following table summarizes the treatment of missing values for variables in the input data sets used by PROC BOM.
Table 3.6: Treatment of Missing Values in the BOM Procedure
Data Set 
Variable 
Value Used/Assumption Made/Action Taken 

Part Master 
Missing, if 

otherwise ignored 

0, if 

otherwise ignored 

Value ignored 

0, if 

otherwise ignored 

Ignored if 

1, if 

otherwise, the value is determined by the procedure 

Product Structure 
Value ignored 

0, if corresponding 

otherwise ignored 

0, if corresponding 

otherwise ignored 

Input error: procedure stops with error message, if this is the first observation; 

otherwise, the value of the 

1, if corresponding 

otherwise ignored 

Missing, if corresponding 

otherwise ignored 
Note that in the Product Structure data set, a missing value is allowed for the Parent
variable only when two or more consecutive observations contain product structure records with the same parent item (see
Output 3.1.1 and Output 3.3.2 as examples). In the Part Master data set, if the Part
variable is missing, the values for the ID
, LeadTime
, QtyOnHand
, and Requirement
variables are ignored by the procedure. If the Part
variable is not missing but the Requirement
variable value is missing, the gross requirement of the item identified by the Part
variable is assumed to be 1 if the item in question is an end item. Otherwise, the gross requirement of this item is determined
based on the dependent demand process. See the section Summarized Parts Data Set for details about the dependent demand process.