Through consistency, we attempt to achieve predictability.I've watched teams put a great deal of effort into improving their estimates. I've seen teams compare stories from this sprint to stories from prior sprints to try to maintain consistency. I've seen teams use a reference story for a single point. When estimating, they look at the reference story and then estimate all others compared to it. These seem like decent practices. The goal of these practices is consistency. Through consistency, we attempt to achieve predictability.
But one thing I've never understood is the notion of estimates versus actuals. Here we look at the original estimate for a story and we then estimate again once the story is complete. The idea here is that the estimate upon completion is an actual. This provides us a learning opportunity whereby we can improve our estimates going forward. This, to me, is a flawed approach. To illustrate my point, let's look at estimations from a slightly different angle.