Every year, Stack Overflow conducts a survey of its users to help inform the development of its community and platform. This year, more than 80,000 developers shared how they learn, the tools and languages they use, and provided all sorts of feedback valuable to Stack Overflow’s direction. The results also present a snapshot of developers and development as of when the survey was conducted.

The results of the 2021 Stack Overflow Survey were recently shared publicly, along with commentary and insight provided by Stack Overflow. We will take a look at some of the more interesting data points as they pertain to data science, data scientists, and all of the many data-related positions and those professionals who fill them.

Developer Profile

 
 
The first section of the survey concentrates on characteristics of the responding developers themselves: demographic information such as age and geographic location; how long they have been coding; how they learned to code; and more.

A few quick and interesting quotes specifically related to learning to code, as well as developer employment, pulled directly form the overview of the survey are shared below, along with some charts summarizing response frequencies to key developer profile questions.

This year, for example, we observed a significant evolution in the way developers educate themselves. For the rising cohort of coders under the age of 18, online resources like videos and blogs are more popular than books and school combined, a statistic that doesn’t hold for any of our other age cohorts. Overall, the profession is full of new joiners, with more than 50% indicating they have been coding for less than a decade, and more than 35% having less than five years in the trade.

Figure 1. Responses to 2021 Stack Overflow Survey question “How did you learn to code?“
 

It is no surprise that almost 60% of respondents learned how to code from online resources. Younger respondents tend to learn from online courses, forums, and other online resources. Older respondents, on the other hand, learned from more traditional mediums like school and books.

81% of professional developers are employed full-time, a decrease from 83% in 2020. The percentage of professional developers saying they were independent contractors, freelancers, or self-employed increased from 9.5% in 2020 to 11.2% in 2021 – indicating potential job insecurity or a shift to more flexible work arrangements.

We now turn our attention to developer education levels for a moment.

Figure 2. Responses to 2021 Stack Overflow Survey question “Which of the following best describes the highest level of formal education that you’ve completed?“
 

70% of all respondents and 80% of professional developers have completed some form of higher education, a bachelor’s degree being the most common.

Other topics discussed in the Developer Profile section include demographic data such as race, sexual orientation, geographic location,

Technology

 
 
Now we move on to the bread and butter of the survey, responses to questions related to what languages and technologies developers are using right now.

Languages

 
First up, languages, the undisputed number one question folks want to see the responses to when they get their hands on this report.

So, what programming, scripting, and markup languages are respondents using for development over the past year?

Figure 3. Responses to 2021 Stack Overflow Survey question “Which programming, scripting, and markup languages have you done extensive development work in over the past year, and which do you want to work in over the next year?“
 

Of particular note to data science types, Python was included in 48.24% of responses, and is currently one of the most used languages by developers.

Note that, while data science language of interest R does not appear in the top responses in Figure 3 (cut of due to the long tail of responses), R was included in 5.07% of responses.

We’ve seen what languages developers are using, but want about the languages developers want to use? What percentage of developers who are not developing with the language or technology but have expressed interest in developing with it.

Figure 4. Responses to 2021 Stack Overflow Survey question “Which programming, scripting, and markup languages have you done extensive development work in over the past year, and which do you want to work in over the next year?“
 

Again, as R does not make an appearance in the top responses in Figure 4, it was included in 2.82% of responses.

And how about the more insightful “work with vs want to work with?“

There is a lot to unpack here, but here are some of the most notable trends we uncovered. There are over 10k Javascript developers that want to start or continue developing in Go or Rust. The majority of developers that want to use Dart are currently using JavaScript. We also see the only developers that want to work in PHP are SQL developers.

This information is housed in an interactive visualization which can best be used directly on the Stack Overflow Developer Survey site.

Databases

 
Moving on to databases… here are the results to the equivalent question gauging use of database products.

Figure 5. Responses to 2021 Stack Overflow Survey question “Which database environments have you done extensive development work in over the past year, and which do you want to work in over the next year?“
 

This is pretty straightforward, but we can see that SQL databases take the top 3 spots, and 4 of the top 5. This seems like a significant continued endorsement of SQL databases by developers.

Cloud Platforms

 
When it comes to cloud platforms, AWS seem to be king, with Google Cloud and Microsoft Azure also possessing significant shares of the market.

Figure 6. Responses to 2021 Stack Overflow Survey question “Which cloud platforms have you done extensive development work in over the past year, and which do you want to work in over the next year?“
 

Interestingly, a comparison of which cloud platforms developers love versus those they dread conforms quite closely with the responses to those platforms which developers have used. It’s also not unreasonable to posit that low adoption of IBM Cloud and Oracle Cloud could be correlated with the fear that developers using it have of using it again.

Figure 7. Responses to 2021 Stack Overflow Survey question “Which cloud platforms have you done extensive development work in over the past year, and which do you want to work in over the next year?“

Other Frameworks and Libraries

 
Looking at both the most used and most wanted other frameworks and libraries, you can see a number of those which are either specifically for data scientists and/or machine learning engineers, or are heavily used by these professions.

While Tensorflow is the most wanted library, Pytorch is a more loved library. As .NET Core users here at Stack Overflow, we’re pleased to see it in the top spot.

It is easy to argue that at minimum 7 of the following libraries and frameworks are very relevant to practicing data professionals, with even more being possible or even likely.

Figure 8. Responses to 2021 Stack Overflow Survey question “Which other frameworks and libraries have you done extensive development work in over the past year, and which do you want to work in over the next year?”
 

Turning our attention to frameworks and libraries that developers want to work with, many of the same data science relevant tools show up here as well.

Figure 9. Responses to 2021 Stack Overflow Survey question “Which other frameworks and libraries have you done extensive development work in over the past year, and which do you want to work in over the next year?”

Learning and Problem Solving

 
As a developer, what do you do when you get stuck? Figure 10 seems to indicate that Google truly is your friend. We all do it…

Figure 10. Responses to 2021 Stack Overflow Survey question “What do you do when you get stuck on a problem?“
 

Salary

 
 
The last thing we will look at from the report is salary data.

Across the board, engineering managers, SREs, DevOps specialists, and data engineers tend to receive the highest salaries. When focusing on the US, we see some differences at the bottom of the salary spectrum. In the US, mobile developers and educators tend to have a higher salary relative to other occupations when compared to the global developer population.

Figure 11. Responses to 2021 Stack Overflow Survey question “What is your current total compensation (salary, bonuses, and perks, before taxes and deductions)?“
 

What impact do tools and technologies used have on your ability to earn?

The report offers a number of variables to correlate salary with; while not a perfect approach, let’s have a look at the category other frameworks and libraries, which seems like an interesting data point for data scientists to investigate. It would seem that this list is dominated by a number of libraries and tools we might use on a daily basis.

Figure 12. Responses to 2021 Stack Overflow Survey question “What is your current total compensation (salary, bonuses, and perks, before taxes and deductions)?“
 

It’s difficult to extrapolate salary based on a single technology, but interesting to look at the top technologies together nonetheless.

 
Related:

• What is a Data Scientist Worth?
• Top Programming Languages and Their Uses
• Data Scientist’s Guide to Efficient Coding in Python