Is metacognition an affective, cognitive, or behavioural variable? Is metacognition an affect or cognitive or behaviour variable ? 

I want to study variation in metacognition and working memory ability level and its effect on inductive reasoning. 
Therefore i am trying to understand the cognitive system.
I read some literature stating that metacognition is cognition awareness, which implies that it is a cognitive variable, but some say that it is an opinion about how far they can do metacognitive ability. I read about a factor analysis of the Junior Metacognitive Awareness Inventory.
It seems like there are a lot of ideas out there as to what metacognition really is.  Having done my MS thesis in understanding how people learn in engineering programs, I typically think about metacognition as "knowing how to learn."  It's typically a goal of engineering education to teach students these skills.  

Therefore, I would say it's mostly a cognitive variable, but it's also a behavior because it's a set of habits about how one thinks.  How are you planning to measure metacognition?  And why inductive reasoning?  Why not critical thinking in general?