An open position in your team is always an opportunity. Leaders know that the fastest way to transform an organization is to bring in new people, or move people into new roles. New hires are also inherently risky. Think strategically!
First, never assume the best response is to fill the position just as it was before. The world changes, your business changes, and your team changes. What’s the best way to use an open position? You could find a good hire to replace the existing role. It’s more likely you can adjust the role responsibilities and scope before filling it. Perhaps your organization needs a person in a completely different role. Give serious thought to closing the position and managing the workload other ways. In large companies open positions are strategic assets in budget and priority conversations.
Then consider the attributes of the person you need in the role. Do you need a disruptor or change leader who can take the organization through discomfort to a better place? Or do you really need a maintainer to manage the status quo (e.g., for a process crucial to your business success)? Is this your opportunity to hire someone who fits in a succession plan? Perhaps you hire the position at a lower level expecting that top talent will be promotable.
Next consider the pros and cons of an internal hire vs. an external hire. I suggest you do this before you create a job description:
Internal candidates are generally known quantities (for better and worse). If this is a promotion situation, I recommend the 150% guideline – can the candidate do 100% of their current role and 50% of this new role? If not, it might be too great a stretch. Internal hires can be better for continuity and team morale, rather than bringing in a relatively unknown person from the ‘outside.’ Counterpoint: it can be difficult for an internal candidate to lead a change effort if they’re already in the group which needs to change the way it works.
External candidates should be considered when you need new skills, new perspectives, and/or a big change. An external hire doesn’t ‘own’ any of the existing processes and workflows which might need to be changed. Use your hiring process to carefully vet candidates – check references, ask them to execute a small project for you to demonstrate their ability, and don’t be fooled by people are better at interviewing than delivering results.
It’s problematic to craft a job description around a person. It’s better to craft the job description and then find the person who best fits that role. There are many sources for help on creating job descriptions; I recommend the Manager Tools process.
Follow the good advice available about interviewing candidates. I published my list of interview questions (and crucially, why I ask them).
Finally, invest in a startup plan for your new hire. Introduce them to key stakeholders. Make sure they have early small wins. Provide coaching and advice about how your organizational culture works. Communicate frequently, and be available to them. The investment early greatly reduces the risks of a failed employee, and will pay large dividends in the future.