Is Timeboxing Bad for Software Development?

I recently made a video, An Introduction to Reference Class Forecasting , where I show how to use a simple, yet reliable, alternative to estimates in software projects. In the video, I touch on the topic of timeboxing , and why it can have the opposite of the desired effects in software development. Timeboxing is generally accepted as a good, even indispensable thing. It is an integral part of Scrum, and other Agile methodologies. (Even the ones I like a lot.) It is worth going into a little bit of detail about how, and why, timeboxing can backfire. What is timeboxing? Timeboxing is a project planning technique where a fixed time period is allocated to an activity. For example, in Scrum, Sprints, Sprint Planning, Sprint Review, and Daily Scrum, are all timeboxed. If we look at other Agile methodologies, like Extreme Programming, Lean Software, Development, and Dynamic systems Development Method (DSDM), they use timeboxing in some shape or form. Kanban is an exception. Note t...