During my formative years, there was a band from the north of England, not far from where I was growing up, called the Happy Mondays. Probably the most notable thing about them was one bandmember called ‘Bez’. His contribution was somewhere between cheerleading and performance art, as all he appeared to do was dance like a maniac while shaking maracas like his life depended on it. Nobody really knew why, yet he was a key member of the band. We couldn’t hear the maracas, so he wasn’t adding anything musically, but somehow the band would not have been the same without him.
Bez is the best metaphor I can think of to describe how most of our community views that strange little xml file that accompanies the SEND xpt files as part of the study package: the Define-XML file. It doesn’t contain data, just information about the data. We are not quite sure what it’s adding, we just know the package wouldn’t be complete without it.
I’ve heard it said that the FDA does not use the Define files. I’ve also heard it said that they do use them, and they are necessary for loading the data. I have seen FDA feedback provided to sponsors which remarks on the Define file. Still, I think there’s some confusion across the industry regarding what the FDA actually do with the Define file.
Most commercial SEND solutions produce some default Define file populated with some basic information, usually based off a generic template and often, not too study specific. The file follows the Define-XML standard, but it isn’t really adding any value. Usually, the intention is that such files are the starting point and it’s assumed that the organization will complete them manually to tailor them to the individual study. From what I have seen, some organizations are doing exactly this, and manually editing the XML. However, some organizations are not doing this and instead, simply supply the default file that has been auto generated.
The three reasons why some organizations only supply the default file, are quite clear:
- They are unsure of the value of a well-formed Define file
- They do not have the necessary tools to produce a well-formed Define file
- They do not have the necessary expertise
This has been the way for some time now, but I’m starting to see a change in the tide here. As mentioned earlier, the FDA often include discussion of the quality of the Define file in their sponsor feedback. Also, tools will continue to be developed and improved to accommodate this.
The Define-XML standard is something separate from the SEND standard. The standard is the same for both clinical datasets (SDTM) and nonclinical (SEND). For this reason, this week I’ve been learning a little about how Define files are both produced and used in the clinical world. It appears that clinical have tapped into the value and purpose of the Define file, yet in nonclinical, we often still view them in a similar way to how my teenage self, viewed that maraca shaking curio.
Maybe in a future post, we can discuss some of the opportunities afforded by having well-formed Define files.
Till next time,