Reliance inside a reporting line runs at 84%; across functions it runs at 9%, and every handoff crosses that boundary.
Why it matters when the plan changes
Both sides of a handoff can be performing well and the handoff can still fail. The upstream team delivers what it understood was needed, the downstream team receives something it cannot use, and each is individually blameless. Managers report they can rely on their own reporting line all or most of the time, a pattern far weaker across functions, and a handoff by definition crosses that boundary. The failure lives in the space between them, which is the only place no measurement is pointed.
The tension is between specification and speed. Fully specifying a handoff is expensive and most handoffs do not need it; each added party multiplies the connections that must be kept in step, so treating every transfer as critical costs more than it saves. The judgement is which handoffs the plan actually depends on, and those are the few worth the cost of writing down what good looks like before the first transfer rather than after the third.
In practice
A data team delivers a feed on the agreed date in the agreed format. The analytics team cannot use it, because it needs one field the specification never mentioned and neither side thought to ask about. Two weeks are lost to a conversation that would have taken twenty minutes before the work started.
Evidence
People rely on their own reporting line far more than on other functions, and a handoff by definition crosses that line.
Donald Sull, Rebecca Homkes and Charles Sull, Why Strategy Execution Unravels and What to Do About It, Harvard Business Review (2015)Every added party multiplies the connections that must be kept in step, so each extra handoff costs more than the last.
Brooks's law, after Frederick P. Brooks, The Mythical Man-Month (1975)
What it cannot tell you
Naming a handoff as the point of failure does not tell you which transfers are worth specifying. Not every handoff carries risk, and treating all of them as equally fragile spends the same effort the concept is meant to save. The judgement about which few matter sits outside the term itself.
Questions
Because the transfer itself is nobody's work. Research summarised in Harvard Business Review found managers rely on their own reporting line far more than on other functions, and a handoff by definition crosses that boundary. Each side is measured on what it produces, not on what the other side can use.
A named person on each side, a written statement of what will be ready and in what form, a date, and an agreed answer to what happens if it slips. The 84% reliance managers report within their own reporting line does not extend across functions, which is why the third and fourth elements matter most.
No. Specifying all of them is expensive and most do not carry the plan. The useful discipline is to identify the few transfers the plan cannot survive losing and specify those properly, while leaving the rest to the working relationship that already handles them.
They multiply and they move. A structure that divides work differently creates new transfer points and quietly retires old ones, and the people who held the informal knowledge of how a transfer worked are frequently now somewhere else. That combination is why delivery slows after reorganisations.
A handoff is one kind of dependency: the kind where something physical passes between parties. Other dependencies are decisions, approvals or sequencing constraints where nothing is transferred but the work still cannot proceed. All of them belong on the same map.