What are the advantages/disadvantages of using default values?

[spuddybike]

This should take in the views of both the content entry person and implementer.

• Raised in context of W3C and its use for, say, a comma delimited file (default values for delimiters, decimal separators, use of blank or "." for missing value, use of " for text, etc.).

[kulnor]

advantages:

• reduces burden as the most common value is already filled out
• helps users that do not know what the element or value is about (we make the assumption that default is then the expected value)

disadvantages:

• lazy users don't pay attention and don't provide the right information...
• risk of having the wrong information when users don't know what to do. In general, there should therefore always have a"don't know" option that can be used instead of default value. This is better than using blank (or in some case don't know could be default value)

[wlthomas]

Discussion in TC on 2019-07-25
Two types of Defaults: Model Default and Binding Enforced Default

Model Default: When a piece of content like the xml:lang in the DDI Instance tag sets the "default" value to a specific language, so you can pull out a single object and not have to worry about an inherited value for some something
DECISION: Anything that can be reused should not have information that has been inherited from a parent object within a specific hierarchy

Binding Enforced Default: Version number defaulted to 1.0 in codelists for codeValues - not all bindings have default values; with XML you have to use a validating parser and pass the defaults through to each object; we have to know how things are being processed as well as binding specific issues
DECISION: the schema should not be required to determine that something is a default - some bindings do not support. Information should be at the level of the reusable object; binding level defaults are not allowed