Toyota, where Lean came from. Doing estimates to put together a car sounds like it would be straight-forward. Doing estimates for R & D, not so much. I think s

Toyota, where Lean came from. Doing estimates to put together a car sounds like it would be straight-forward. Doing estimates for R & D, not so much. I think software development falls somewhere in between those 2 extremes. We have some knowable quantities, but also some unknowns. We can't really estimate the unknowns reliably, but we can do something like a "timebox" to see how much we can figure out. Meaning that we need time up front, just so that we can come up with an estimate.