WCAG 2.0 - Is summary attribute a must for table elements

Question

I'm a bit confused about WCAG 2.0 Documentation. I have two questions:

1) In H73: Using the summary attribute of the table element to give an overview of data tables, it is stated that

"If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance."

and actually most of the criterias have this text. What does it mean? Since it is not written that summary attributes are mandatory, is it optional to include summary attribute?

2) There are sufficient techniques area and failures area. If a criteria is listed in sufficient techniques area and when failures area doesn't mention that criteria, does it mean that criteria is optional?

Answer 1

You are mixing up the technique and a criterion, see the chart for the hierarchy. The techniques (h73), have the text you quoted because of two reasons:

1. Some criteria's have more than one technique associated with it*
2. This allows use for future best practices that may not have gone through the appropriate W3C/WAI vetting processes yet. So when you are creating the document that claims your compliance, you can say I did x, y, and z which isn't/aren't W3C techniques, but I deem them accessible so they meet criteria 1.x.x - think WAI-ARIA here.

*- The technique you pointed out is not a good example of this, however if we stay in the realm of <table>s, we can look at techiques H63 and H43. Criterion 1.3.1 deals with table mark-up and lists those two techniques. I cannot comment how many people know, so I will point to the HTML Spec. The HTML 4.01 Spec mentions that you need to use the scope or header attribute(s) to be valid HTML, I am sure the HTML 5 Spec does as well, but I haven't read it too closely.

To get back to your question, if you are creating a HTML5 page/site/whatever, the summary attribute has been declared obsolete, so you cannot use it legally (read more:HTML Mailing list, and W3C Wiki). Instead you should use the techniques mentioned in the HTML 5 link in the above paragraph.

2) There are sufficient techniques area and failures area. If a criteria is listed in sufficient techniques area and when failures area doesn't mention that criteria, does it mean that criteria is optional?

The sufficient techniques area outlines known ways to make something accessible which meet the ruling criteria guideline. The failure area says "The following are common mistakes that are considered failures", in other words, "provided all the other information on this page (or the ones we link to), developers try to do the following stuff instead - and most of the time aren't accessible." An example would be instead of using a <label>, they use a placeholder attribute.