WCAG2 lists several techniques as sufficient for most of the success criteria that make up the guidelines. Content authors sometimes are not sure which particular technique they should implement in order to meet a success criterion. The problem is compounded in some cases by the fact that sufficient techniques for some success criteria like SC 1.1.1 (Non-text Content) or SC 1.3.1 (Info and Relationships), are grouped by sityuation-A or situation-B etc. And while in many instances a technique is independent of other techniques, in some cases, a technique needs to be implemented in conjunction with another technique in order to satisfy a particular success criterion.
The content author needs to implement a technique or techniques that will meet the success criterion. The advice of an experienced accessibility consultant is often very useful in making this decision. While one technique may be suited in one situation, a different one may be appropriate in another. Picking one technique instead of another because of its ease of use or for the sake of consistency, may lead to a sub-optimal accessibility experience for users and sometimes may even be regarded as an abuse of a technique.
Guidance from W3C in Understanding WCAG 2 Techniques
Refer to the response  from the WCAG-Working Group. Also note its advice:
- From an author’s perspective: If you use the sufficient techniques for a given criterion correctly and it is accessibility-supported for your users, you can be confident that you met the success criterion.
- From an evaluator’s perspective: If web content implements the sufficient techniques for a given criterion correctly and it is accessibility-supported for the content’s users, it conforms to that success criterion.
Authors are encouraged to apply all of the techniques where appropriate to best address the widest range of users’ needs.
Case Study: SC 2.4.1 (Bypass Block)
Consider SC 2.4.1 (Bypass Block): There are two groups of techniques listed. General Technique G123 and G124 from the first group may be applied only where there is more than one repetitive block of content like a top navigation and a secondary navigation. On the other hand, technique G1 applies where there is a single block of content that may needs to be bypassed , like a main navigation menu before the start of the main content section .
(Incidentally,the SkipTo plugin by PayPal Accessibility Team is a useful tool for implementing G124).
Secondly, the second group of techniques like headings, landmarks do not benefit keyboard only users unless browser specific plugins work reliably and are in common use , . So I am in favor of appending a note to the end of the techniques for SC 2.4.1 in the same manner as is done for SC 3.3.2 (Labels or Instructions).
Therefore, it is my practice to suggest use of one of these 3 techniques (G1, G123, G124) and suggest proper use of WAI-ARIA-landmarks only as a supplementary navigational aid that benefits a subset of keyboard-dependent users.
This is how I would re-cast the sufficient techniques for SC 2.4.1 Bypass Blocks:
Sufficient Techniques for 2.4.1 – Bypass Blocks
Creating links to skip blocks of repeated material using one of the following techniques:
- G1: Adding a link at the top of each page that goes directly to the main content area
- G123: Adding a link at the beginning of a block of repeated content to go to the end of the block
- G124: Adding links at the top of the page to each area of the content
Grouping blocks of repeated material in a way that can be skipped, using one of the following techniques:
- H69: Providing heading elements at the beginning of each section of content
- H70: Using frame elements to group blocks of repeated material
in conjunction with
H64: Using the title attribute of the frame and iframe elements
Note: The techniques at the end of the above list should be considered “last resort” and only used when the other techniques cannot be applied to the page. The earlier techniques are preferred because they increase accessibility to a wider user group.