To be able to officially declare that leadership is taking leaps forward, one must be able to measure the success of leadership. This in itself is a whole world of discussion. Successful leadership means booming companies, but companies can nethertheless do well ‘despite’ leaders rather than ‘due to’ good leadership, meaning the stock index is not a measure of leadership success.
It would seem that qualitative measures must be used – i.e. the accounts of leaders throughout history as a comparison to modern leaders. But this is also a difficult area, as historic accounts of leaders were written during a different period of culture, and therefore the same characteristics of leaders may be perceived, evaluated and documented differently to today. Indeed, changes in leadership may amount to little more than culture change than an abrupt improvement in the quality of leadership itself.
One could perhaps measure leadership by identifying how many leaders per year were in the public eye, creating positive change. But then factors such as the pervasiveness of media coverage, as well as political interference would upset this analysis. As you can probably tell, the task of measuring leadership is a lot harder than it might first have seemed.
One could look at the change in popular leadership theories over a period of time, but the question is raised as to whether current leadership theories are actually absorbed by managers in any significant way – or rather, their managements styles may be more affected by the past experiences and bosses than any abstract paper by a management academic or leadership author.
A final idea for measuring leadership styles is to ask leaders themselves – are leaders today better than leaders 10, 20, 30 years ago? But this may be affected by their personal biases – all those asked would have been at a much more junior level 30 years ago, and therefore would have looked up at leaders (for better or for worse) through a different lense indeed.