Rules for pre-specified lengths of --TESTCD

s Steven

on September 30, 2013

Dear all,

I understand the new request from the FDA to reduce unnecesary space usage in variables by limiting variable lengths to the length of its longest value. I'm just wondering how in practice this can be attained for --TESTCD's.

According to SDTMIG 3.1.3: "--TESTCD and IDVAR will never be more than 8, so length can always be set to 8." I can imagine in certain circumstances, like in an LB domain, most LBTESTCD values are shorter than 8 characters.

For example: the maximum length of all values in LBTESTCD is 4. Which rule does then apply?

- should the variable length of LBTESTCD be fixed to 8?

- or should the variable length of LBTESTCD be reduced to 4?

In my opinion, the 2nd option should be followed. But what are your thoughts? Is there any OpenCDISC rule which checks this?

Thanks in advance & kind regards,

Steven

Forums: SDTM

s Sergiy

on October 1, 2013

Hi Steven, I agree that it's

Hi Steven,

I agree that it's quite confusing. Please note, that variable length issue is specific only to particular data formats. E.g., it exists for SAS XPORT, while it's not applicable for ODM.

There is no one good rule to fit all user needs, standards requirements, particular use cases, etc.

We believe that validation specifications should be split or created for particular use cases. E.g., SDTM compliance or FDA submission. FDA has problems with huge datasets with a lot of waste space. The most simple and straightforward approach is to re-size SAS XPORT data to actual maximum value of each variable. However you should do it only before sending your data to FDA, but before a submission data transfer you can handle variable lengths according your company data management practice.

Kind Regards,

Sergiy