How does Agile help with long term planning?
I'm often involved in discussions about Agile that question its efficacy in one way or another. This is, in my view, a very good thing and I highly encourage this line of inquiry. It's important to challenge the assumptions behind Agile so as to counteract any complacency or expectation that it is a panacea to project management ills. Even so, with apologies to Winston Churchill, Agile is the worst form of project management...except for all the others.
Challenges like this also serve to instill a strong understanding of what an Agile mindset is, how it's distinct from Agile frameworks, tools, and practices, and where it can best be applied. I would be the first to admit that there are projects for which a traditional waterfall approach is best. (For example, maintenance projects for nuclear power reactors. From experience, I can say traditional waterfall project management is clearly the superior approach in this context.)
A frequent challenge the idea that with Agile it is difficult to do any long-term planning.
Consider the notion of vanity vs actionable metrics. In many respects, large or long-term plans represent a vanity leading metric. The more detail added to a plan, the more people tend to believe and behave as if such plans are an accurate reflection of what will actually happen. "Surprised" doesn't adequately describe the reaction when reality informs managers and leaders of the hard truth. I worked a multi-million dollar project many years ago for a Fortune 500 company that ended up being canceled. Years of very hard work by hundreds of people down the drain because projected revenues based on a software product design over seven years old were never going to materialize. Customers no longer wanted or needed what the product was offering. Our "solution" no longer had a problem to solve.
Agile - particularly more recent thinking around the values and principles in the Manifesto - acknowledges the cognitive biases in play with long-term plans and attempts to put practices in place that compensate for the risks they introduce into project management. One such bias is reflected in the planning fallacy - the further out the planning window extends into the future, the less accurate the plan. An iterative approach to solving problems (some of which just happen to use software) challenges development teams on up through managers and company leaders to reassess their direction and make much smaller course corrections to accommodate what's being learned. As you can well imagine, we may have worked out how to do this in the highly controlled and somewhat predictable domain of software development, however, the critical areas for growth and Agile applicability are at the management and leadership levels of the business.
Another important aspect the Agile mindset is reflected in the Cone of Uncertainty. It is a deliberate, intentional recognition of the role of uncertainty in project management. Yes, the goal is to squeeze out as much uncertainty (and therefore risk) as possible, but there are limits. With a traditional project management plan, it may look like everything has been accounted for, but the rest of the world isn't obligated to follow the plan laid out by a team or a company. In essence, an Agile mindset says, "Lift your gaze up off of the plan (the map) and look around for better, newer, more accurate information (the territory.) Then, update the plan and adjust course accordingly." In Agile-speak, this is what is behind phrases like "delivery dates emerge."
Final thought: You'll probably hear me say many times that nothing in the Agile Manifesto can be taken in isolation. It's a working system and some parts if it are more relevant than others depending on the project and the timing. So consider what I've presented here in concert with the Agile practices of developing good product visions and sprint goals. Product vision and sprint goals keep the project moving in the desired direction without holding it on an iron-rails-track that cannot be changed without a great deal of effort, if at all.
So, to answer the question in the post title, Agile helps with long term planning by first recognizing the the risks inherent in such plans and implementing process changes that mitigate or eliminate those risks. Unpacking that sentences would consist of listing all the risks inherent with long-term planning and the mechanics behind and reasons why scrum, XP, SAFe, LeSS, etc., etc., etc. have been developed.
Image by Lorri Lang from Pixabay