Stack Overflow today launched Salary Calculator, a tool that lets developers check out typical salaries across the industry. The calculated results are based on five factors: location, education, years of professional coding experience, what kind of developer you are, and the technologies you use professionally.
Stack Overflow is releasing the tool because the company believes developers should be empowered with more information around job searches, careers, and salary. The company noticed that ads on Stack Overflow Jobs that include salary information get 75 percent more clicks than ads without salary information. Even in the case when the salary range is below average, the ads still get 60 percent more clicks.
So the team concluded a salary calculator would best differentiate its developer jobs board from the competition.
Based on the location, education, experience, and other information you enter, the calculator reports a 50 percent prediction interval. That means half of the people with the same characteristics as you to have salaries within that range. Spanning the 25th to 75th percentiles, the interval gives you a range of expected salaries. Salaries in the calculator are reported in the local currency for each user.
The salary calculator is based on data from the Stack Overflow Developer Survey, which saw some 65,000 respondents this year. Of those, only 3,000 offered their salary and happened to work in the first five countries the calculator supports (Canada, France, Germany, the U.K., and the U.S.), Stack Overflow data scientist Julia Silge told VentureBeat.
Silge explained how the model works: “The great thing about multiple linear regression is it allows us to control for, all other things being equal, how much does using some technology make your salary go up? All other things being equal, how much does an extra year of experience make your salary go up? So that’s the real power of the statistical approach that we’ve taken here.”
This matters because location is the first and arguably most important factor for the calculator’s results. Stack Overflow is exploring how to best add support for more countries, but that’s not as easy as it may seem since data can vary within countries. Developers typically have higher salaries in cities with high housing costs, for example.
To factor this in, Stack Overflow used IP addresses to geolocate survey respondents. The company didn’t include this personally identifying information in the public release of its 2017 survey, but it did assign separate predictions to cities with many developer respondents sharing salaries that were unusually extreme compared to the national average.
The last two factors are also important. Developer salary depends on developer role and type, as you can see below.
This is just the first version of the calculator. Stack Overflow is asking developers to share their salary directly in the tool — the company promises your salary information will only be used to improve the model’s predictions and will never be shown on your public profile or shared with employers. Employers can also use the calculator to learn more about industry salary ranges and the competitive marketplace for developers’ skills.
“We believe strongly that more transparency and more information is empowering for both sides,” Silge explained. “We want developers to use it as a way to find out what they could be making and we want our clients, who are companies [that are] hiring, to be able to use it to understand what would be normal for them to be paying. We want it to be a two-sided tool.”