Primary attribute

Hi everybody,

During our last teleconference we were discussing about the need or convenience of having a "primary" attribute for the "rule" element. The following is an attempt to summarize the discussion so far.

You can see the TCDL 2.0 description of the attribute at [1], but in brief it specifies whether a rule is "primary" (yes) or not (no), being primary rules those against which the test case is supposed to be evaluated (other rules are supposed to be just informational)

So, the two options that were discussed are:

1 - Allowing just one single (always primary) rule per test sample


- It could help to simplify test samples and metadata (the primary attribute won't be necessary any more)

- This approach follow test cases development best practices as, generally speaking, a good test case should be atomic [2], testing a single feature at a time. (Note that in some cases compound tests are necessary, e.g. a test that check the combination of "border-top-color" and "color" in CSS, but this may not be the case in WCAG as success criterion are intended to be independent)


- Even with minimal test samples we could find frequently that more than one rule (success criteria) may be applicable. What to do then with those that are not the primary rule? 

For example:

If we take sc3.3.1_l1_019 [3] we see that the primary rule here is WCAG2 SC 3.3.1 [4], but there are other potential applicable rules such as WCAG2 SC 3.3.2, 3.3.6 or 1.3.1.

2 - Allowing multiple rules (primary or informational)


This way we could look for more completeness on test samples, reporting about any related or applicable rule apart from the primary one.


- In same sense it may be incompatible with the "Clear Scope principle" at the Content Review [5], at least as currently stated.

- Do we have any use case where this could be a benefit in our context? (Apparently no one of the current submitted test samples has a non-primary rule).

- What is the common criterion we all can follow to agree when a rule is primary or not? Will full completeness always be required?
Note also that we have two possible variants within this option:
  A - Allowing just one primary rule and several other informational ones
  B - Allowing several primary (at least one) and informational rules

I think nobody was in favour of the later, but we can easily see how the complexity would increase (For example, what's the criterion to decide if a rule should be primary or not).

Finally, another related issue is the use of the "complexity" attribute for the "testCase" element [6] whose values are "atomic", if it applies to only one accessibility rule (checkpoint, success criterion...) of any kind of rules set (WCAG 1.0, WCAG 2.0 or Section 508), or complex if it applies to multiple accessibility rules from the same set. So, apparently, if we finally decide to follow option 1 (just one single rule) the "complexity" attribute will also turn to unnecessary.

If we follow option 2 (multiple rules) I'm not sure if this attribute may be necessary, as the number of rule elements may give you the same information (atomic if one or complex if more). Additionally, we should clarify if it takes into account just primary rules or also informational ones.

I hope this could help to advance on this issue discussion.
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Waiting for your thoughts. Regards,

Carlos Iglesias

Fundación CTIC
Parque Científico-Tecnológico de Gijón
33203 - Gijón, Asturias, España

teléfono: +34 984291212
fax: +34 984390612

Received on Tuesday, 8 January 2008 09:09:43 UTC