What qualifications are a useful measure of competence

The industry is awash now with qualifications costing a fortune to gain – many in boot-camp guaranteed pass training centres. Meanwhile there are thousands of qualified and very experienced people overlooked because they have all the practical skills and experience without the paperwork to “prove” it. What do you think counts most? Practical and proven skills or in-depth knowledge? What qualifications do you find give the best measure of a persons abilities?