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 These posts contain previously unpublished Salary Survey data.

In a letter to Elizabeth Virginia Wallace dated Sept. 5, 1911, future U.S. president Harry S. Truman wrote that, "There is nothing better than cake but more cake," an observation that perhaps inadvertently ranked the future Mrs. Harry S. Truman behind both "cake" and "more cake" and possibly explains why, notwithstanding a proposal of marriage that same year, the hoped-for nuptials did not actually occur until 1919.

Setting aside its hierarchical hiccups, future President Truman's confectionary contention reflects a familiar and deeply rooted human tendency to suppose that if [Thing] is good, then more of [Thing] is almost inarguably better. Marie Antoinette's real problem was that she didn't tell the peasants, "Let them eat more cake." (Yes, we know, Marie Antoinette didn't actually say that. Print the legend, Mr. Intelligent Trousers.)

For a variety of reasons, this pattern of thinking is often applied to IT certifications: If it's good to have one IT certification, then it must be better to have more than one IT certifications. Better because having more certs demonstrates a certified IT worker's self-motivation and commitment to professional development. Better because having more certs keeps certified professionals abreast of evolving technologies.

Better, most would say, because having more certs adds directly to the stockpile of knowledge and skills that any IT pro uses to approach his or her job. Better, many might suggest, because having more certs helps to maintain a learning mindset and sharpen one's ability to assimilate new information and turn it to productive use. How about better because having more certs contributes to earning a higher salary?

That's the sort of thing that we use our annual Salary Survey to (provisionally) gather data about. Before we get to that, however, let's establish some larger facts about the pool of 2021 Salary Survey respondents who have multiple tech credentials.

About 76 percent of the more than 4,000 respondents to our 2021 Salary Survey have six or fewer active certifications. To break it down a little further, that's more than three-quarters of all survey respondents who have either one (14 percent of those surveyed), two (15.4 percent), three (16.9 percent), four (12.3 percent), five (10.3 percent), or six (7 percent) current IT credentials.

There's a comparative trickle of respondents thereafter, with small numbers of folks who have seven (4.9 percent of respondents), eight (3.4 percent), nine (1.5 percent), 10 (4.3 percent), 11 (1 percent), 12 (1.5 percent), 13 (0.6 percent), 14 (0.7 percent) or 15 (0.5 percent) active certifications.

That's not quite everybody, of course. The survey lets you indicate whether you have 16 or more active certifications. Think about that: 16 active IT certifications — or (gulp) some number that's more than 16. In that group, we find the remaining 5.7 percent of all survey respondents. Those folks are made of something rare and precious. We salute them.

We covered some of that ground in the January issue of Certification Magazine, albeit with fewer details. Here's what we didn't cover at the time, and what we're curious about today. Generally speaking, does having more certs mean that you also earn more money? Is there any degree of correlation? This is what turned up when we crunched the numbers:

In general terms, there is an overall upward trend in salary that corresponds to the increase in number of active IT certifications held. You can see it more clearly in the United States, although the overall pattern is there in the numbers for countries outside the United States as well.

As we've seen from drawing up similar tables in previous years, if you're on a career path that leans heavily on one or two key certifications, and doesn't require constant renewal of any others, then you can probably still do just fine for yourself. At the bottom of the table, where a large range of certifications is represented by a single data point, there is a solid six-figure salary number for U.S. professionals.

Deeper down the chart, of course, we ran into the expected problem of not having enough individual respondents who hold a certain specific number of certs to create a reliable average.