How can you assess technical skills in candidates using coding challenges?

1 Define the objectives and criteria

Before you create a coding challenge, you need to define what you want to assess and how you will measure it. Depending on the role and the level of seniority, you may want to test different aspects of technical skills, such as logic, syntax, data structures, algorithms, design patterns, testing, debugging, or performance. You also need to decide on the scoring system, the time limit, the difficulty level, and the feedback mechanism. You should align these elements with the job requirements and the expectations for the candidates.

2 Choose the format and platform

There are different formats and platforms for coding challenges, and each one has its advantages and disadvantages. You can choose between online or offline, live or asynchronous, individual or collaborative, open-ended or multiple-choice, and so on. You should consider the trade-offs between the convenience, the validity, and the engagement of each option. For example, online platforms can save you time and automate the evaluation, but they may not reflect the real work environment or the collaboration skills. You should also pick a platform that suits your budget, your technical stack, and your candidates' preferences.

3 Design the problem and solution

The problem that you ask the candidates to solve should be clear, relevant, and challenging, but not too complex or unrealistic. You should avoid using trick questions, obscure concepts, or irrelevant details that may confuse or frustrate the candidates. You should also provide enough information, instructions, and examples to help the candidates understand the problem and the expected output. Moreover, you should have a reference solution that you can use to compare and evaluate the candidates' solutions. The solution should be correct, complete, and optimal, but also flexible enough to accommodate different approaches and styles.

4 Evaluate the code and skills

When you review the candidates' solutions, you should look beyond the correctness and completeness of the code. You should also analyze the quality and efficiency of the code, such as the readability, the structure, the modularity, the naming, the comments, the indentation, and so on. You should also check the performance and scalability of the code, such as the time and space complexity, the edge cases, the error handling, the optimization, and so on. Furthermore, you should assess the skills and knowledge that the candidates demonstrated, such as the problem-solving, the logic, the creativity, the use of data structures, algorithms, frameworks, libraries, tools, etc.

5 Provide feedback and follow-up

The last step of assessing technical skills using coding challenges is to provide feedback and follow-up to the candidates. You should give them a clear and constructive feedback on their strengths and weaknesses, their score and ranking, and the areas for improvement. You should also thank them for their time and effort, and inform them about the next steps of the hiring process. Additionally, you should ask them for their feedback on the coding challenge, and use it to improve your design and implementation. You should also keep in touch with the candidates until you make a final decision, and be transparent and respectful throughout.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?