What action should a Scrum Master take to maintain developer performance and high velocity?

Maintaining developer performance and high velocity is largely about ensuring that the team can work efficiently without interruptions. By removing impediments that hinder the Developers, the Scrum Master fosters an environment where the team can focus on their work without external disruptions that may slow them down or decrease their effectiveness.

This approach aligns perfectly with the principles of Scrum, where the Scrum Master's role is to support the team by addressing obstacles that may prevent them from achieving their goals. When impediments are removed, Developers can make decisions more freely and focus on delivering high-quality work, ultimately maintaining or even increasing their velocity.

In contrast, assigning tasks based on expertise could lead to bottlenecks or dependencies, which can disrupt flow. Updating Scrum boards daily, while important for transparency and communication, does not directly influence performance or velocity. Assisting Developers with coding and testing might compromise the self-managing nature of the team and could undermine the Developers' ownership of their work. Thus, the most effective action a Scrum Master can take in this context is to remove impediments.