The Critical Skills Visa was introduced in May 2014 and has become one of the most-used visa categories. Persons with specific skills and experience can get a work visa even if they do not yet have a job offer. The "critical skills list" is long and complex and contains a number of hidden traps and challenges.
When ploughing through the pages and pages of industries, roles and qualifications, it is often difficult enough to find a fit - especially when degree or qualification and role or experience are not a clear match. Add to this the fact that for many of the categories there exists no professional body, or none that allows for registration and/or is willing or authorized to issue confirmations of skills.
Some professional bodies have published certain criteria, and some of these are significant and may change frequently (e.g. trade tests for artisans). Others are very professional and efficient. Make sure to take expert advice before plunging yourself into this process, it will likely save you a lot of time and wasted money.