Working on a support team, I see many questions concerning “why an error is being triggered” and “how to fix this error”. This is especially true when working with the Study Tagging Files XML which is a very common area of confusion for most people new to eCTD and XML in general. I have spent a lot of time creating the XML for sequences by hand, and have examined sponsors’ XML to determine the location of the error. Because of these experiences, I thought it would be beneficial to discuss the basic structure of the index.xml, stf.xml, and the single most common question I receive related to the STF which is, “Why am I seeing errors 1952, 1953 and are these the same error?”
Index.xml File Basics
First, here’s the quick primer on the index.xml file. I’m not going to get too deep into the index.xml file, but what you need to know is that the index.xml contains one or more “leaves” which control your file reference in a viewer. This leaf will contain the file reference title, a path which points to the actual file in your file structure, and other values such as an append operation. The leaf will appear in a specific area in the index.xml (e.g. M2-4), and this placement will control which section the file reference will inhabit inside a viewer.
EXAMPLE – (Note: information has been removed from the leaf for readability)
In this example, a viewer will show a file reference with the title of “Nonclinical Overview” appearing in the ICH eCTD section “2.4 Nonclinical Overview” and this file will point to “nonclin-overview.pdf”.
Study Tagging Files Basics
With regards to Study Tagging Files XML, or STFs, the leaves in the index.xml are still added in the same way, so if you are working on a study for section “126.96.36.199 Bioavailability (BA) Study Reports” all of your documents will be added to this section in the same manner. The one difference is that you now need one additional leaf which will be for your stf.xml file. Now the STF is similar to the index.xml file in that it contains “leaves” which are actually “doc-content” sections. It is these sections that will reference each document leaf you have added to the study section in your backbone. This is where I may have lost some people. The key takeaway here is that the stf.xml file contains valuable information to display your study in a viewer, such as title, ID, and categories like species and the “doc-content” sections will tell the viewer which study sub-section should be used to place your file reference.
EXAMPLE – (Note: the index.xml would contain a leaf in 188.8.131.52 for the stf.xml and one for the document with an ID of “int248”)
In this example, a viewer will show a study section for “184.108.40.206 Bioavailability (BA) Study Reports” with the Study ID of “GS 2010-111” the Study Title of “My example Bioavailability Study” and this study would contain a study sub-section “Study Report Body” with the file reference from the index.xml file inside of this subsection.
The Most Common STF Error Question
Last but not least this brings me to the most common STF error question, “Why am I seeing errors 1952, 1953 and are these the same error?”
Error 1953 is when the title listed in your index.xml leaf, that is for the stf.xml file, does not match the title listed inside of stf.xml file. The title for your study section displayed in a viewer should come from the stf.xml file, but in the past this title may have been pulled from the leaf in the index.xml. Because of the two possible locations for a Study Title error, 1953 is triggered when they do not match to assure that no matter the viewer your desired title will always be displayed.
Error 1952 relates to the title in the leaves for your actual documents (excluding the leaf for the stf.xml) matching the title listed in the “doc-content” section that references the leaf. In the above stf.xml example, the “doc-content” section is “pointing to” a leaf in the index.xml with the ID of “int248”.
How to Handle Errors 1952, 1953
Now you may have noticed that the example does not have a title in the “doc-content” section, and if you have looked at a recent stf.xml file you may be asking yourself, “Where are these titles that he just mentioned?” For STF v2.2 these title are not listed in the guidance, and are listed as optional in the “ich-stf-v2-2.dtd”. These titles are, however, mentioned in the STF v2.0 guidance which was the basis for the error. Because these titles are not required for v2.2 and not mentioned in the guidance, you do not need to add them to the “doc-content” sections in the stf.xml. This error is really a carryover from v2.0 and is currently being phased out.
If you refer to the current draft “Specification for eCTD Validation Criteria” posted by the FDA on December 10, 2010, then you will see this error has been retired and will be replaced by 1950. You may also notice there is no 1950 listed in the draft guidance. During the draft process, it has been decided to use the existing error 3001 rather than create error 1950.
So the bottom line is that if you see error 1952 and your v2.2 stf.xml “doc-content” sections do not contain titles you can ignore this error. If you see error 1953 you should make sure that the same title is used for the title inside the stf.xml and the title present in the leaf “pointing to” your stf.xml file.