The 96-minute rule is a productivity guideline recommending that knowledge workers set aside that period of time each day to address their most crucial tasks.
Essentially, the 96-minute rule says that people should dedicate themselves to their most important work for 96 minutes, avoiding multitasking and protecting themselves from interruptions and distractions such as phone calls, email and instant messaging, web browsing and social media. The first 96 minutes of the work day are generally considered the most effective, although that may vary from one individual to another.
The rule is derived from the Pareto principle. According to the Pareto principle, 80% of outcomes are determined by 20% of the inputs. In this case, for example, 80% of a worker's output is accomplished in 20% of that worker's time. Randy Mayeux, a corporate trainer, devised the rule by calculating 20% of an eight-hour work day. The 96-minute rule is fairly congruent with management expert Peter Drucker’s claim that 90 minutes is the smallest effective time period required for meaningful knowledge work.
The effects of distraction on productivity have been demonstrated in a number of research studies. A study by Basex, a research firm based in New York, found that workers were distracted or interrupted, on average, every 11 minutes and that it took them an average of 25 minutes to return to their original tasks.