The short answer is that yes, we do.
Program management refers to the coordinated oversight and management of an assortment — the technical term is portfolio — of related projects. This is often done with varying degrees of formality through a PMO (Project Management Office.)
Strategy and tactics vs. operations
A program manager relies on project managers to provide insight as to the specifics of individual projects that allow for an understanding of the cross-project dependencies. A project manager is concerned with specific operational outputs, whereas a program manager is more concerned with tactical or strategic outcomes, prioritizing shared resources across projects, and minimizing overall risk. Note that a portfolio of projects does not necessarily make a program, only their coordinated oversight does.
At a hospital, a program manager may oversee a “patient safety program” with the overall goal of achieving zero harm, and with a portfolio of individual projects having to do with prescribing, dispensing, and monitoring — ex. bar-coding in the Pharmacy, bar-coding and medication administration at the bedside, drug build-and-test inside the Pharmacy module of an IT system, developing means for identifying patients unequivocally, etc. These projects are focused on getting the 5Rs right — right drug, route, time, dose, patient. A program manager is not an island, and relies also on other areas and their inputs, including technology assessments, policy, and so on.
Whereas a project’s success is judged by the metrics of delivering to specification, on time, and preferably under budget, a program is typically assessed over a longer time frame and in terms of strategic benefits. A program manager is like a chess player who, depending on the situation of the game board, may decide to attack with certain pieces (projects) and even sacrifice others to achieve the desired strategic outcome.
Program management draws on process and systems engineering skills, and it is vital in breaking the siloed approach to projects, gaining an understanding of project inter-dependencies, and being able to manage resources with a view to achieving specific long-term outcomes at an acceptable level of risk.
Asking if an organization needs program management is akin to wondering if a football team needs a quarterback. Project management focuses on doing projects right, whereas program management is all about doing and overseeing the right projects.