According to the Enneagram, a Type One is sometimes described as a perfectionist. This type is seeking perfection because they find meaning and value in doing what is right and good. Type Ones are motivated by a strong moral, and much for of their self-worth originates in their belief that their value is reliant upon their ability to do what is good and true.
In a PLC, a Type One may present as someone who initially needs a fair amount of clarity around exactly what is expected from the collaboration and work. It's not so much that they want to control or lead the work, they simply want to ensure they know what is expected so they can meet expectations.
It can be difficult for a Type One to work with others who do not hold the same values that they do--especially around quality of work. For many in this group, they believe their is a best or right way that things "should be done," and they want to follow the "right" plan.
A Type One's worst case scenario is not "pulling their weight" in the group or team. They would rather let themselves down than not meet a perceived expectation of what someone else expects them to do. The second worst case scenario is having a teammate who does not pull their weight. A Type One veteran teacher may find it slightly frustrating to work with a newer teacher who does not yet have the skill set to create or execute in a project.
Type Ones are open to collaboration and in fact appreciate it, when it is done well. They do not enjoy team projects where they have to monitor substandard work (which is almost always all work that is completed because if it is not perfect, the Type One experiences frustration).
Type Ones may enjoy making materials (so they can ensure quality control or correct font usage) and they also respect deadlines, agendas, and accountability. A Type One may appreciate a bit of oversight from the principal or district because they prefer to work in a system where everyone is held to high standards (including themselves).
The Type One's biggest critic is themselves, so remember that if your teammate seems to shut down, withhold ideas, or withdraw. It may not be that they don't want to collaborate; it may be that they are afraid or nervous to share their work out of fear of inadequacy.
Anything less than perfect can be a bit hard for a Type One, so looking at data could be triggering, or it could be liberating. They may also be some of your best formatters or designers in the building, so if you need something to look good--reach out to a One.
Type Ones like to live in the reality of what is and then work to make it the best it can be. In some ways, the responding to data portion of a PLC may be where a Type One thrives--because they want to things to be good, better, best--so they are willing to try and try again.
Some words to describe an Enneagram One are loyal, dedicated, organized, efficient, true, hard-working, fair, honest, and integrity. Enneagram Ones do what they say they will do. In fact, they will try to get you to do what you should say you should do, too.