Project management: what does switching tasks cost?
A schedule can add up in hours while remaining fragmented in practice. The management question is precise: should tasks belonging to the same project be grouped together rather than alternating repeatedly between projects during the day?
What the literature establishes
Sophie Leroy (2009, Organizational Behavior and Human Decision Processes) examines “attention residue”: when someone switches tasks, some of their attention may remain attached to the previous one. Her experiments show that leaving an unfinished task can compromise performance on the next task. Being available in the schedule therefore does not mean being immediately available in cognitive terms.
The mechanism behind task switching
Joshua S. Rubinstein, David E. Meyer and Jeffrey E. Evans (2001, Journal of Experimental Psychology: Human Perception and Performance) show that switching between experimental tasks entails a time cost associated with cognitive control. Shifting goals and activating the relevant rules are not instantaneous operations. This mechanism differs from attention residue, but both studies caution against treating transitions as neutral time.
The premature conclusion
One might conclude that each person should work on only one project. These studies do not establish an optimal number of concurrent projects or demonstrate that every interruption is harmful. A quality alert or a decision that unblocks a partner may justify a transition; the issue is to distinguish necessary switches from avoidable fragmentation. (our executive and employee training programmes)
What the schedule cannot reveal
These experimental findings do not directly measure the effects of reorganising work in a Fribourg company. An aggregated timesheet also fails to distinguish one uninterrupted session from several interrupted sessions. Task complexity, urgent requests and dependencies between functions must therefore be documented before delays are attributed solely to context switching.
A practical check in Fribourg
Within SHR’s “Project Management” programme, a proposed exercise in Fribourg could focus on a project involving an agri-food business, a bilingual industrial partner and a team from the university hub. Compare two periods of equal duration: one using the usual arrangements, the other grouping work into project-specific blocks while maintaining a channel for urgent requests. Record project switches per person per day, then calculate the proportion of deliverables accepted by the agreed date without major rework, using a criterion defined at the outset. This would provide a local check without turning any improvement into causal proof or assuming that bilingualism is responsible for interruptions. To go further: explore the Project Management training in Fribourg, or browse our executive and employee training programmes in Switzerland.
In pictures: Project Management in Fribourg
- project management
- Fribourg
- research
- training fribourg