HackerRank began analysis by looking at which test types are most popular among developers. HackerRank developers can choose to participate in 15 different domains, but some are more popular than others. The following table shows the proportion of completed tests that come from each domain.
The most popular domain by far is algorithms, with nearly 40% all developers competing. This domain includes challenges on sorting data, dynamic programming, and searching for keywords and other logic-based tasks. For algorithms tests, developers can use whichever language they choose, which may partially explain why it’s so popular. Algorithms are also crucial for coding interviews, so it could explain why more coders would practice algorithm challenges. At a distant second and third, Java and data structures coming in at about 10% each. Distributed systems and security are our least popular tests, though we still receive thousands of completed challenges in those areas.
So based on these tests, which country has the programmers that score the highest?
In order to find out, we looked at each country’s average score across all domains. We standardized the scores for each domain (by subtracting the mean from each score and then dividing by the standard deviation; also known as a z-score) before finding the average. This allows us to make an apples-to-apple comparison of individual scores across different domains, even if some domains are more challenging than others. We then converted these z-scores into a 1-100 scale for easy interpretation.