What is the one thing to change within the workforce to get the most improvement?
This is a semantic minefield, where we must be clear whether practices are part of the workforce or the work systems. I.e. how wide is the “within” the workforce?
If people are within the system (and often victims of it) then “within the workforce” can be limited to culture, talent, and behaviour, and perhaps roles and organisation, though I wouldn’t.
Then the one thing would be treat them like respected adults.
With the exception of professions which need to dehumanise people to enable them to kill, force and punishment are unacceptable behaviour. Very much a secondary point is that psychological violence get suboptimal results from knowledge workers (results are ok for slaves, and agricultural, industrial, and clerical workers).
Oh, you want to change them?
You can’t do that, not directly and not quickly. Nor do you have the right. They’re people not machinery.
Shape the system to the people, not vice versa. Work with what you’ve got. Culture will emerge slowly over time.
Which brings us to the one thing to change about the system: decision mechanism. Change the way decisions are made. Our friends Dan Mezick claims this will change culture in three days. We might not be quite so optimistic, but the principle is great.