Take a moment to consider the following question:

What is the most important thing about retrospectives?

Is it that they take place regularly?

Is it that they involve the whole team, and nothing but the team?

Is it that the results are actionable?

I don't know that there is one most important thing, because all of the above can make or break retrospectives. I've been places where retros barely took place; I've attended retrospectives where few people showed up; and I've been to ones that were little more than “shoot the breeze” or venting.

Let me offer one more answer: A trained, impartial facilitator.

You might already know that retrospectives need facilitation. Facilitation turns a retrospective from group discussion to structured discovery, one that results in action (and doesn't get hijacked by dominant personalities).

But there's more to retrospectives than process and moderation. You can easily collect “worked well”, “needs improvement”, and practical action items that are all superficial or obvious.

Deep retrospectives are where the money is. In them, team members talk about what really hurts, what truly doesn't work for them, and it's these introspections that really have the team move forward, grow, and perform better.

As such, they can be a pretty sensitive affair. Hence the first thing any retrospective facilitator must do is establish a safe environment.

Most of the new to Agile have double trouble there: One, they have few (if any) people who can, or care to facilitate properly. Two, their chosen retrospective leader is rarely impartial.

If your facilitator is one of the team members, that will hamper or bias their participation. And if it's a person of authority (worse yet, the boss of some team members), you won't get much useful input.

You might go with the default choice: the ScrumMaster or team coach. Again, their neutrality and skill might fall short of the needs. Some ScrumMasters are managers or team leads; even without meaning to, they might intimidate some team members into silence.

ScrumMasters sometimes have yet another handicap, which has to do with their former role or the expectations from them. As retrospective leaders, they must truly not be invested in its outcome. They lead the reflection process and serve the team — whatever the team might discover or decide. For relatively rookie ScrumMasters, that's a scary attitude.

So what can you do? As part of your Agile implementation, each of your teams must have access to people who can lead impartial retrospectives.

These folks can be “home-grown”, borrowed from other teams, or even from HR. They must learn and develop these skills. You might want to hire out for the first couple of retros, as an example and training opportunity for them. I wouldn't recommend rotating the role among team members: nobody learns deeply this way.

The value of properly-run deep retrospectives cannot be underestimated. You'll do well to invest in them. Let me know how I can help you.