Instruction: Outline the steps you would take to design a study that accurately measures the causal impact of a new algorithm on user engagement. Ensure your answer addresses potential pitfalls that could introduce selection bias and how you would mitigate them.
Context: This question evaluates the candidate's ability to design a rigorous study in a tech environment, focusing on causal inference principles. It tests their understanding of selection bias, their ability to anticipate and mitigate it, and their knowledge of experimental design in a real-world tech scenario.