You’re right, there is a high variability in the complexity in physical tasks just based on factors you cannot predict. The quality of things that impact physic

You’re right, there is a high variability in the complexity in physical tasks just based on factors you cannot predict. The quality of things that impact physical work versus software is fundamentally different. I see people on here post construction projects as the poster child for things that can be estimated with traditional project management techniques. This is wrong because most construction projects come in over cost and over schedule. This can be because materials costs change, labor costs change, the soil at your site may not be what you expected, weather impacts, and stakeholders may demand something different after the project is estimated. Although these are unknown quantities, these factors existence are known. Whereas in software, you’re more likely to encounter unknown unknowns. These are factors that nobody thinks are even possibilities until you run into them because nobody has done anything similar before. An example from my experience is when I was working on implementing a marching cubes algorithm on a GPU, we did research to make sure that you could do it. But when it came time to implement, we found that the cube data was expressed as a set of faces, and not a set of vertexes and no efficient algorithm existed for that expression of the data that could be mapped to a single instruction multiple data paradigm. We could not preprocess the data to convert it to vertexes because it would not offer any speed up if we did. To implement the acceleration we wanted, you’d have to change how the data was stored in the application. Which is a very different project with very different timescales. We ended up abandoning the effort and moved to other work. This happened because we made a discovery that no one could have predicted, in the implementation, that had an unknown impact. In physical projects, you might find there are a lot of unknown things that can happen, that you may not predict. You can certainly reduce this by bringing in experts to a project, people who have seen much more than you. Certainly there is still potential for black swan events. But these are rare. Where as in software, the experts you may bring on may not necessarily know more than you, you are frequently your own expert. Black swan events in software projects are common.