SD1082 - FDAC036 Variable length

Pinnacle 21 General General Discussion
1

The FDA036 rule says: “Variable length should be assigned based on actual stored data to minimize file size. Datasets should be re-sized to the maximum length of actual data used prior to splitting”. As someone translating rules in code, I would say that the rule is pretty “fuzzy”. Essentially, the FDA rule FDAC036 (in the P21 interpretation) is more strict than the SDTM-IG. It means that when your longest test code is 7 characters, you should set the variable length to 7.

The background of all this is that SAS-XPT is spoiling bytes. For example, if you have one value for a variable that is really 200 long, and all other values for the same variable are only 1 long, you will need to set the variable length to 200 due to that one value. In the SAS-XPT file, all other values (being 1 long) for that variable will have 199 blanks to fill the field. What a waste!!!

It is really time that the FDA starts accepting other “smart” formats like XML or JSON.

2

4.1.2.9 Variable Lengths
Very large transport files have become an issue for FDA to process. One of the main contributors to the large file sizes has been sponsors using the maximum length of 200 for character variables. To help rectify this situation:
• The maximum SAS Version 5 character variable length of 200 characters should not be used unless necessary.
• Sponsors should consider the nature of the data, and apply reasonable, appropriate lengths to variables. For example:
o The length of flags will always be 1
o –TESTCD and IDVAR will never be more than 8, so length can always be set to 8
o The length for variables which use controlled terminology can be set to the length of the longest term.

the above is from SDTM IG 3.2. should we exclude --TESTCD and IDVAR when we validating the length? otherwise we always get an error when we follow the SDTM IG and set the --TESTCD length to 8.

Thanks!