Salary Survey Extra is a series of periodic dispatches that give added insight into the findings of our most recent Salary Survey. These posts contain previously unpublished Salary Survey data.

In 1974, farmers attempting to dig a well near the Chinese city of Xi'an made a remarkable discovery. The diggers uncovered a collection of life-size earthenware figures that had stood undisturbed for more than 2,000 years. Successive excavations turned up more than 8,000 individual sculptures, since dubbed the Terracotta Army, originally created to honor the burial of Qin Shi Huang, the historical first emperor of China.

The individual terracotta figures have similar face shapes, but it is generally believed that no two of them, across the entire burial site, have identical features. You'd think that the workers conscripted by the emperor's court would have maybe created a dozen or so basic types and then repeated them over and over. But perhaps even if that had been the intent, variety would have crept in anyway.

It's sort of the same way with professional IT careers, in that no two career arcs are identical. There is no one ideal mold from which every successful IT career must be (or, indeed, has been) struck. Most people end up hitting a lot of the same benchmarks on the path to professional success, but there are no rules that everyone, without exception, must follow.

If there's no one magic formula, however, there are likely some career preparation and career building options that will provide a more effective foundation of IT knowledge and skills than others. We asked that question of the thousands of certified IT professionals who participated in our annual Salary Survey, to find out which methods of job preparation they would recommend.

Each survey respondent rated the effectiveness of five primary means of preparing to work full-time in IT. The number indicates the percentage of all individuals surveyed who ranked each mode of learning and development at each given level of effectiveness. Here's what we learned:

Q: How effective are the following methods at preparing an average individual to succeed in a professional IT job role?

College Education
Extremely effective — 13.3 percent
Very effective — 20.3 percent
Effective — 35.2 percent
Somewhat effective — 23.2 percent
Not very effective — 8percent

Certification
Extremely effective — 21.2 percent
Very effective — 40.4 percent
Effective — 28.5 percent
Somewhat effective — 8.5 percent
Not very effective — 1.4 percent

Self-instruction/Learn by doing
Extremely effective — 32.1 percent
Very effective — 36.4 percent
Effective — 24 percent
Somewhat effective — 6 percent
Not very effective — 1.5 percent

Specialized technical training provider
Extremely effective — 23.7 percent
Very effective — 43 percent
Effective — 24.7 percent
Somewhat effective — 7.2 percent
Not very effective — 1.4 percent

Workplace training
Extremely effective — 35.2 percent
Very effective — 36.4 percent
Effective — 20.4 percent
Somewhat effective— 6.7 percent
Not very effective — 1.3 percent

There's a surprising lack of belief at least in the high-level effectiveness of a college education at preparing one to succeed in IT. Quite a few certified IT professionals, apparently, would downplay the importance of attending college and getting a degree before entering the IT workforce. That's particularly intriguing given that more than 85 percent of those surveyed hold some level of college degree.

Certification has strong 'very effective' and 'effective' numbers, but only a smallish core of respondents believe certification is an 'extremely effective' method of preparing one to succeed in the IT workplace. Here again, context adds intrigue: every person who participated in the survey holds at least one current IT certification.

There appears to be a great deal of self-confidence among certified IT professionals. More than 68 percent of those surveyed think that either figuring stuff out on one's own or using self-study materials like books and videos is either extremely effective or very effective as preparation to succeed in IT. There's also high confidence in specialized technical training providers, schools, boot camps, or professional associations that directly teach core IT skills.

It would appear that workplace training, however, trumps every other method of preparation to succeed in IT. There are probably two ways of looking at that: You could plan to go in with solid foundational skills and learn the specifics by actually doing the work. Or maybe the implication is that you build up skills and knowledge by volunteering or working in low-pressure part-time jobs until you're ready for the big leagues.

Each of the categories has its true believers, of course. So if something seems like it would be extremely effective for you, then that solution probably will, in fact, serve you well. There's no one mold that will guarantee success for everyone whose career is shaped by it.