I happen to agree with Brian on that one :)  Also note that changing from the DTD to the schema may require some reworking of your style sheets - seems like there was a post on this subject not that long ago.

The biggest benefit of the schema vs the DTD is that the schema allows you to enforce a wider range of constraints on things like actual attribute values (hence the question about @mainagencycode).  So for example, we use the DTD and then run the files through RLG's EAD Report Card which (among other things) tells us if @normal for <unitdate> isn't in the right format.  If we were using the schema, the schema would check for that during the editing/authoring/validation process.  Basically the schema adds another level of QA/QC during authoring.


From: Encoded Archival Description List [mailto:[log in to unmask]] On Behalf Of BRIAN TINGLE
Sent: Thursday, April 28, 2011 11:23 AM
To: [log in to unmask]
Subject: Re: DTD v. Schema

I think schema is more of a pain to work with.

The main difference is the namespaces.  EAD DTD is not in any xmlns namesapce; EAD schema uses two different namespaces (the EAD isbn: uri is the xmlns for EAD, and it uses xlink in the xlink xmlns.  The case is different on some of the xlink linking attribute values where they use camel case in schema and all lowercase in DTD.

Then there are minor differences where schema is more restrictive than the DTD like Mark observed yesterday.

At OAC we accept schema based EAD, but we convert to EAD 2002 DTD internally.

On Apr 28, 2011, at 7:56 AM, Nathan Tallman wrote:

Mark's last email has prompted something that I've been meaning to ask this list for a while. What are the practical benefits of migrating to schema based EAD from DTD? I know that XML-wise, DTD is the older style and schema is the new, so that schema is the preferred new format. But, I don't think DTD support is going away anytime soon. Are people just trying to achieve the gold standard, or am I missing some other practical benefit. Is a schema easier to work with?

Also, if someone wants to migrate from DTD to schema, are there any guides or other resources available? The EAD Tools & Helper Files page <> doesn't have anything. I'm assuming the EAD XML files will need more updating other than the DTD declaration, but maybe it's as easy as that...


Nathan Tallman
Associate Archivist
American Jewish Archives