Productivity of the human greatly vary depending on the technology use for doing it.
for standard measurements you can always refer the respective state guidelines.
The difference in guidelines and actual productivity is the technological advancement
Example
Conventional formwork system requires more efforts and labours to make one floor, also it take more time.
Aluminium Formwork, requires less labours, time due to easy fit and less weight. it makes construction faster.
In both cases productivity of the workmen varies, in case of aluform, semiskilled labours gives more productivity than that of labour working in conventional system.
Now add one more technology in work - Tower Crane - the productivity will boom further.
So it is better to measure the actual productivity by monitoring actual works which are done using currently adopted technology at your company. this will give you accurate productivity details.