Productivity as ("work done" / "hours worked")?
So, before they did 100 worth of work in 40 hours per week = 2,5
Now, they did the same 100 worth of work in 36 hours per week = 2,78
A ~11% increase in productivity.
Then, the company changed the meetings. From the article:
The standard duration for a meeting was slashed from 60 minutes to 30 — an approach that was adopted for nearly half of all meetings. In a related cut, standard attendance at those sessions was capped at five employees.
In a blog post announcing the plan in July, Microsoft Japan said there was often no reason for meetings to run an hour, or to tie up multiple people from the same team.
Some meetings lasting half the time and having less participants. That may explain the remaining 29% increase of productivity (for the total of 40%).
Microsoft may increase productivity further by changing to three work days per week and limiting a employee to just one meeting per week. Or just abolishing all stupid unnecessary meetings. Meetings are just the biggest time wasters at work.